Glossary of Road Design and Construction Terms
Glossary of Road Design and Construction Terms
3-C Planning
The continuing, cooperative,
comprehensive planning
process in an
urbanized area as
required by federal
law.(e.g. Lincoln, Omaha, or
Sioux City Area
Planning)
3R Project 3R stands for
resurfacing, restoration and
rehabilitation.These
projects are designed
to extend the
life of an existing
highway surface and
to enhance highway
safety.These projects usually
overlay the existing
surface and replace guardrails.
3R projects are
generally constructed within the
existing highway right-of-way.
Abutment An abutment
is made from
concrete on piling
and supports the end
of a bridge
deck.
Access Control The extent
to which the
state, by law,
regulates where vehicles may
enter or leave
the highway.
Action Plan
A set of
general guidelines and
procedures developed by each
state to assure
that adequate consideration
is given to possible
social, economic and
environmental effects of proposed
highway projects. All
states were directed
to develop this plan
by the Federal
Highway Administration.
Adapted Grasses Grasses which
are native to
the area in
which they are planted,
but have adjusted
to the conditions
of the environment.
Adverse Environmental
Effects Those
conditions which cause
temporary or permanent damage
to the environment.
Aesthetics In the
highway context, the
considerations of landscaping,land use
and structures to
insure that the
proposed highway is pleasing
to the eye
of the viewer
from the roadway and
to the viewer
looking at the
roadway.
Aggregate
Stone and gravel
of various sizes
which compose the major
portion of the
surfacing material. The
sand or pebbles added
to cement in
making concrete.
Aggregate Base
Course The
layer of material
immediately beneath the pavement.
It may be
composed of crushed
stone, crushed or uncrushed
sand and gravel,
or combinations of
these materials. To provide the
service intended it
must be uniform in
strength to support
the pavement.
Air Pollutants
Those impurities which
cause the atmosphere
to become contaminated. These
include: carbon monoxide,
nitric oxides, sulfur dioxides,
particulates, and hydrocarbons.
Air Pollution The
presence of contaminating
particles in the
air which interfere with a person’s
health, safety or
comfort,personal property, plants and animals.
Air Rights The
property rights for
the control or
specific use of a
designated air space
involving a highway.
Alignment The vertical
and horizontal location
of a road.
Alternate Routes The various
general highway locations
examined in corridor studies
to determine the
best alignment for a
highway.
Ambient Air Any unconfined
portion of the
atmosphere; the outside
air.
Apportionment Method used to
determine the share
of funds each
state highway administration receives
from the Federal Government.
Archeological Salvage
Program Program
to protect Indian
sites or locations of
historical interest which
will be disturbed
by plowing, leveling, clearing,
dozing, etc., for
excavation and investigation by
professional archeologists.
Archeology The scientific
study of material
remains of past
human life and activities.
Arterial A general term
denoting a highway
primarily for through traffic, usually
on a continuous
route.
Asphaltic Cement
Brownish black, solid
or semisolid mix
of bitumens from native
deposits or a
petroleum by-product used
in the manufacturing of
asphaltic concrete.
Average Daily
Traffic or ADT A measurement of
the number of
vehicle which use a
highway over a
period of a
year divided by 365
to obtain the
average for a
24-hour period.
Backfill Material
used to replace,
or the act
of replacing, material removed during
construction. Also, may
denote material placed, or
the act of
placing material adjacent
to structures.
Backslope The slope
from the bottom
of the ditch
to natural ground,on
the opposite side
of the foreslope.
Band of
Interest The
area included in
a corridor study
which will be examined
for the best
alignment.
Berm A raised mound
of earth used
in different ways;
as a site barrier,
used to separate
the roadway embankment
from a drainage way, as a sound barrier, or for architectural reasons.
Bicycle Lanes
Portions of a
roadway set aside
for bicycle use,
with the lanes distinguished
from the motor
vehicle portion of the
roadway by painted
stripes, curbs, or
parking blocks.
Bicycle Routes
There are three
types - Bicycle Trails, Bicycle
Lanes and Shared Roadways.
Bicycle Trails Separate paths
or trails intended
for the exclusive
use of bicycles. When such
a path is
part of a
highway, it is separated
from the roadway
for motor vehicle
travel by an open space
or barrier.
Bitumen A natural asphalt
or substance found
in a natural
state or a residue
by-product from petroleum
refinement.Bituminous Containing
Bitumen Board of Public
Roads Classification &
Standards This Board
develop minimum design, construction
and maintenance standards for
each functional classification of
public roads and streets.
The 11-member board
is appointed by the
Governor and approved
by the legislature
for 4-year terms. Two members
represent the NDOR. (Contact the
Government Affairs Division
for more information.)
Borrow Excavation
When the Department
specifies a new
roadway to be constructed, the
roadway embankment is
usually constructed from earth
available on the
right-of-way,however, if there
is insufficient earth
the contractor isrequired
to obtain the
needed additional material
from off the state’s
right-of-way (land). This material
is called borrow excavation
Borrow Pit
The source of
approved material required
for the construction of
embankments, or other
portions of earthwork requirements.
Borrow Pit
Restoration Returning
the area used
for borrow to a
usable condition.
Box Culvert A box
culvert is cast-in-place
or pre-cast reinforced concrete and
has a box
shape that is
located under the embankment to
drain water from
one side of
the road to the
other.
Bridge Deck
Scarification To
remove the existing
concrete bridge driving surface in
preparation for a
concrete overlay. This is usually
done with a
cold milling machine
consisting of hardened steel
bits attached to
a revolving drum.
Bridge Pier A bridge
pier is
a supporting structure
at the junction
of connecting spans of
a bridge.
Buffer Zone
The area
15 feet from
the edge of
the roadway surface including the
rest of the
right-of-way which is
planted with native and
adapted grasses and
provides habitat for wildlife.
Bypass Routes An arterial
highway that permits
traffic to avoid
part or all of
an urban area.Capacity Maximum number
of vehicles which
has a reasonable expectation of
passing over a
given section of
a lane or a
roadway in one
direction during a
given time period under prevailing roadway and traffic
conditions.
Cement A powdered product
made by grinding
clinkers of limestone, clay,
and other materials,
and which reacts with water to
form a rock
like substance used
to bond aggregates together
in concrete.
Centroid An assumed
point in a
zone that represents
the origin or destination of
all trips to
or from the
zone. Generally, it is
the center of
trip ends rather
than a geometrical
center of zonal area.
(Also called Zone
Centroid)
Channel Path
in which water
will or does
flow.
Channel Change The change
in direction of
the natural path
of water flow, usually
for a short
distance.
Channel Clean
Out The
removal of debris,
soil deposits, or
heavy brush in an
existing path of
water flow.
Channel Excavation
When the Department
builds a new
bridge or drainage structure
over an existing
waterway it is sometimes
necessary to dredge
out or straighten
the existing waterway channel.
This work is
called channel excavation.
Channelization (of
road) The
direction of the
traffic flow into
definite paths, by means
of traffic markings,
islands, or other means.
Cofferdam When the
Department specifies the
construction of a bridge
pier in, or
adjacent to a
stream, the contractor
may be required to
drive sheet piling
into the stream,
creating a cofferdam. The
mud and additional
stream bed material that
must be excavated
prior to the
construction of the pier
is called cofferdam
excavation.
Cold Milling To
prepare an existing
bridge deck or
roadway pavement for resurfacing,
the department sometimes
creates a new roadway
cross section and
profile by cold
milling the existing surface
with a machine
that has hardened
steel bits in a
revolving drum.
Collector Consists of
a group of
highways and/or streets
which pick up traffic from
many local or land-service
roads and carry it to community
centers or to the arterial
system.They are the
main school bus
routes, mail routes,
and farm-to-market routes.
Collector Street A
street which serves
the internal traffic
movement within
the city
and connects with
the major arterial
system.
Commodity Flow
Path that
products follow because
of division of
labor and specialization. For
example, oranges are
produced in Florida and
travel to other
states for consumption.
Community Participation Participation by
the public in
the highway planning process
at orientation, information
and public hearing meetings,
membership on committees,
and through participation in
surveys and interviews.
Community Values The
social, economic and
environmental factors unique to
a given community.
Concrete Concrete
is a building
material made of
sand and gravel bonded
together with portland
cement into a
hard,compact substance.
Concrete Revetment
Mats As an
alternative to concrete
riprap along a ditch
or waterway bank,
sometimes a concrete
revetment mat will be
used. The mat is
a heavy fabric
envelope which is pumped
full with cement
mortar that hardens and conforms to
the shape of
the surface upon
which it is placed.
Connecting Link A roadway
on the state highway system
which extends between and
junctions with two
other numbered routes on the
state highway system.
Such roads are
usually relatively short in
length.
Construction Costs
Those costs after
the contract has
been let. This includes engineering, survey,
inspection, in addition to those
actual construction costs.
The written contract between the
Department and the
contractor setting forth the
obligations of the
parties, including, but
not limited to,the
performance of the
work, the furnishing
of labor and materials, and
the basis of state highway
payment.
Contract Specifications The
requirements which are
to be followed
in the construction of
highways.
Cordon Line
An imaginary line
encircling a survey
area defining the limits
of the internal
survey and location
of external traffic survey stations.
Cordon Stations
Stations located on
each street crossing
the cordon line where
vehicles were counted
and classified during
survey hours.
Cordon Survey A
roadside-interview type of study
in which drivers
are stopped and questioned
about origin and
destination of their trip
and its purpose.
The interviews are
conducted at stations on
the external or
internal cordons, or
on both.
Correlation An interdependence between
variables.
Corridor An area
of variable width
between two points.
In highway work, corridors
are defined areas
where the needs
for improvement are studied.
Corridor or
Location Public Hearing Public
hearing held by the
Department of Roads
to inform the
public and obtain
their views on a
proposed project location.
Corridor Study
The study of
corridor locations, social,
economic and environmental considerations, and
alternatives for an
area.
Cost Benefit
Ratio A method
of determining the
economic justification of alternative schemes
for highway system
improvements.The benefits and
respective costs for
each alternative are
determined and the
ratio of benefits
to cost for
each project is compared
to the others.
County Roads
Those roadways which
are constructed and
maintained primarily by county
governments and which
are not on the
state highway system.Cul-de-sac A local street
open at one
end only, which
allows vehicles to turn
around.
Culvert Any structure,
not classified as
a bridge, which
provides an opening under
the roadway.
Dead End
A local street open
at one end
only and with
no special provisions for
turning around.
Decibel A unit of
sound measurement.
Deck Slab
Repair The
wearing surface of
a bridge must
first be repaired before it
receives a new
wearing surface. The
deck slab repair usually
consists of partial
and full depth
patching followed by resurfacing.
Defense Access
Funds Federal
funds are available
without regard to apportionment among
the states for
paying all or
any part of the
construction and maintenance
of defense access roads
(including bridges, tubes,
and tunnels) to military reservations, to
defense industries and
defense industry sites, and
to the sources
of raw materials.
The funds may be used
to replace existing
highway and highway connections, or
to upgrade roads
used for military purposes.
Department of
Roads Nebraska’s state
highway agency which
has the responsibility for
initiating and carrying
forward the planning, design,
construction, and maintenance
of highways on the
state and federal
highway systems.Referred to
as the Department.
Design Capacity
Maximum number
of vehicles which
can pass over
a lane or roadway
during one hour without
operating conditions falling below
a preselected design
level.
Design Hourly
Volume A volume
determined for use
in design representing the
traffic that is
expected to use
the highway in any
designated year. It
is an hourly
volume, usually the 30th
highest hourly volume
expected during the design
year.
Design Life Initially
figured to be
a 20-year period
for pavement.
Design Phase
The development of
a project from
the conclusion of the
corridor location work
to the completion
of final plans.
Design Public Hearing Public
hearing held by
the Department to
inform the public and
to obtain their
views on the
design features of a
project.
Design Speed A
speed determined for design and
correlation of the physical
features of a highway which
influence vehicle operation.
Design Standards
Specifications for such design features
as curvature,grades, roadway
width, drainage facilities,
etc.
Design Volume A volume
determined for use
in design, representing traffic expected
to use the
highway 20 years
in the future.Unless
otherwise stated, it
is an hourly
volume.
Design Year Year
of initial construction,
plus 20 years.
Destination The zone
in which a
trip ends.
Detector Loop New
traffic signal installation
contracts usually include
the construction of a
wire detector loop
placed under the surface
of the pavement
in the approach
area of the intersection. When
a motorist drives
over the detector loop, the
time phase for
the light is
affected.
Detour The route
used for through
traffic around construction areas.
Diffusion Models A
mathematical model to
estimate pollution concentrations from a
specific source.
Dikes A bank, usually
of earth, constructed
to control or
confine water.
Divided Highway A
highway with separated
roadways for traffic
in opposite directions.
Draft Environmental
Impact Statement A preliminary written
summary of the probable
effects a highway
project will have
on the environment, especially
the human environment.
Drain Tile An underground
pipe to handle
water from a
farm field or used
to fix areas
on the right-of-way
to lower water tables.
Drainage Easement
Easement for directing
the flow of
water.
Drainage Structure
Those structures other
than drains, levees,
and pumping plants which
are intended to
promote or aid drainage.
The term includes
catch-basins, bulkheads, spillways, pipe
outlets, etc.
Drop Structure A
particular type of
drainage structure used
to carry water under
or away from
the roadway with
a vertical drop
built into the structure.
Earth Excavation On a
construction project that
requires new or
relocated roadway, the earth
which must be
moved from one
place to another is
called earth excavation.
Easement A right to use or
control the property
of another for designated purposes.
For example, drainage
easement,planting easement, scenic
easement, sight line
easement and slope easement
are five types
of easements in connection
with highways. Easements
may be either temporary or
permanent.
Ecology The inter-relationships of
living things to
one another and to
their environment, or
the study of
such inter-relationships.
Economic Interaction
Mutual impact between
the community and
a road or project.
Ecosystem The interacting
system of a biological community
and its non-living environment.
Ecotone A transition area
between two adjacent
ecological communities
usually exhibiting competition
between organisms common to
both.
Egress The exit
points on a
controlled access highway.
Emergency Relief
Funds Funds
for repair or
reconstruction of highways on
the federal-aid highway
system are available
upon application of the state highway
department, if an emergency
has been declared
by the Governor,
and concurred with by
the Secretary of Transportation. Such funds
may also be
spent on repair
and reconstruction of forest
highways, forest development
roads and trails,
park roads and trails
and Indian reservation
roads, whether or not
such highways, roads
or trails are
on the federal-aid system.
Eminent Domain The power
of the state
to take property
for public use without
owner’s consent upon
payment of just compensation.
Emission Rates The rate
at which the
average automobile is
expected to emit various
air pollutants.
Emulsified Asphalt An
emulsified asphalt is a common
construction material used to
prime, seal or
resurface a highway.
It consists of an
asphalt that is chemically
mixed with water in
an emulsion.
Environmental Impact The effects
a project will
have upon the environment, especially
the human environment.
Environmental Impact
Statement A written
summary of the
probable effects a project
will have on
the environment, especially the human
environment.
Erosion Control
Measures Those
standards used to
retard deterioration or destruction
of the land
surface.
Excavation The act
of taking out
materials, the materials
taken out,or the
cavity remaining after
materials have been removed.
The Department has
an agreement with
the Nebraska Historical Society
to permit the
removal (excavation) and
preservation or salvage
of anything of historical
or archeological value
that may be
found during highway construction.
Exhaust Emissions The air
pollutants emitted from
the exhaust of the
internal combustion engine,
namely carbon monoxide,nitrogen oxides,
and hydrocarbons.
Expansion Tie
Anchors Whenever
the Department widens
a pavement or constructs
new curbing adjacent
to an existing
concrete pavement, these accessories
are tied to
the old pavement by
use of steel
anchor bolts drilled
into the vertical
edge of the pavement.
Expressway A divided arterial
highway for through
traffic with full
or partial control of access and
generally with grade separations at
major intersections.
External Cordon A
line encircling the
study area within
which the detailed
study is
conducted.
External Survey The phase
of the survey
in which traffic
data was obtained by
interviewing motor vehicle
drivers passing through survey
stations on the
principal highways or streets
entering the survey
area.
Federal
Authorization Congress
authorizes the apportionment
of a stipulated amount
of money to
be divided among
the states in given
fiscal year. Apportionment of
this total among the
states is made
by the Secretary
of Transportation.
Federal Highway
Administration A division of
the Department of Transportation, formerly
the Bureau of
Public Roads.The federal
agency responsible for
supervision and distribution of
federal funds to
various state highway agencies.
Federal-Aid Highway Four
categories are; Interstate, primary, secondary and urban.
This is the
system which is
normally eligible to receive federal-aid
funds.
Federal-Aid Interstate
Funds Funds
from the Highway Trust
Fund, designated for use
on the Interstate
highway system.The
provisions governing appropriations, apportionment, and matching
ratios for state
participation differ from those applicable to
other federal-aid highway
systems.
Federal-Aid Interstate
System A highway system
designed and located to connect by
routes, as direct
as practicable, the principal
metropolitan areas, cities
and industrial centers, to
serve the national
defense and to
connect at suitable border points
and routes of
continental importance. The routes
are selected by
joint action of
the state highway departments of
each state and
adjoining state subject
to approval by the
Secretary of Transportation. This
system is located in
rural and urban
areas.
Forecasting
Procedure for
estimating future land
use, population and traffic patterns.
Foreslope The slope
from the edge
of the shoulder
to the bottom
of the ditch or
to the bottom
of the roadway
fill.
Forest Highway
Funds Funds
made available from the U.S. Treasury to be used for survey, construction,
reconstruction and maintenance.
These are appropriated
to FHWA and then apportioned annually
among the states
according to a formula
based on the
area and value
of national forest lands
within a state
in proportion to the total
area and value of
all national forest
lands. Funds for
forest development roads and
trails are appropriated
to, and apportioned by, the Secretary
of Agriculture according to the
relative needs of
the various national
forests.
Funds are
authorized for construction
of forest roads which
are of primary
importance to the
state, counties, or
communities within, adjoining
or adjacent to the national forest
and which are on the
federal-aid system.
Frontage Road A local
street or road
located on the
side of an
arterial highway which permits
access to residences
and businesses from the
controlled intersection of
the arterial highway.
Functional Classification Identification of
a road by
the function it
serves.
Functional Design The determination
of precise alignments
of a road
in an established corridor. From
the functional design,detailed plans
are later developed
which result in
final design.
Geotechnical Fabric
Prior to the
placement of riprap
on an earth
bank adjacent to a
stream, the Department
first requires the placement
of this woven
cloth made from
nylon types of material
that are not
bio-degradable.
Grade Separation A
crossing of two
highways, or a
highway and a
railroad, at different levels.
The bridge that
spans highways or railroad
tracks (as in
an overpass) is a
grade separation structure.
Gradient The percent
of vertical or
longitudinal slope.
Ground Cover
Grasses or other
plants grown to
keep soil from
being blown or washed
away.
Groundwater Table The
level of water
under the earth’s
surface.
Growth Center
Funds Those
funds which can
be allocated to
the three growth center
areas for use
on primary and
secondary projects.
Growth Centers
Those areas designated
as such by
the Federal Highway Administration for
the purpose of
studying economic growth performance.
The areas are
Norfolk, Scottsbluff, and
Tri-city area (Grand Island, Kearney and Hastings).
Growth Factor
Method A procedure for
forecasting travel by
projecting present travel patterns
forward on the
basis of anticipated growth in
different areas.
Guard Rail
A steel rail with
two corrugations at
the shoulder edge
of a highway, usually in front of roadside hazards. Also cable
guard rail.
Habitat Total
environmental conditions of
a place that
is occupied by an
organism, a biological
population or a
community.
Highway Commission An eight-member
appointed board which
serves in an advisory
capacity to the
Governor. The Board serves as
a liaison with
the public and
chairs public hearings. All commission members
are appointed for
a six-year term by
the Governor with
the consent of
the Legislature.Each represents
a highway district
and no more
than four are from
the same political
party.Highway Commission meetings are
open to the public and
generally held the fourth
Friday of every
month at the
central headquarters building of
the Nebraska Department
of Roads in
Lincoln,Nebraska.
Highway-Oriented Business
Businesses purposely built
adjacent to highways to
serve the traveling
public. These include:motels, gas
stations, restaurants, gift
shops, etc. Highway, Street or
Road A general term
denoting a public
way for purposes of
vehicular travel, including
the entire area within
the right-of-way.
Highway Trust Fund Source
of almost all federal-aid for
highways. The fund consists
of the federal
taxes paid by
highway users on gasoline;
special motor fuels;
trucks, truck trailers
and buses; tires of
the type used
on highway vehicles;
tread rubber; and on
certain vehicles and
other items related to highway use.
The tax revenues
are deposited in the
Trust Fund and
then redistributed to
the states in accordance
with formulas established
by law.
Home-
Interview Survey This
survey includes a
series of interviews conducted at
a sample of dwelling units
throughout the study area.
In addition to
origin and destination
of trips made by
residents, information is
also obtained as
to the time, purpose,
and mode of
travel used for
these trips during weekdays.
Data on car
ownership and population are other
by-products of this study.
Also, sociological and economic
data are collected.
Horizontal Curve
(of Highway) Bend
from a straight
line or course
along a roadway.
Human Environment The total
of all external
conditions and influences (aesthetic, ecological,
biological, cultural, social,
economic,historical, etc.)
that affect the
life of a
human.
Hydraulics A branch of
science that deals
with practical applications (as the
transmission of energy
or effects of
flow) of water or other
fluid in motion.
Hydrology The study
of water in the
atmosphere, on
the surface, and underground.
Impact Attenuators A crash
cushion which collapses
to dissipate the energy of an impacting vehicle to prevent
injury. Impact attenuators are commonly
used where roadways
separate or split.
Improvement Any
change to the
design, structure or features of an existing road
or highway. (e.g.
resurfacing, reconstruction,guard rail
replacement, lighting or
landscaping)
Information Meeting
Informal presentation of
information by the
Department relating to a proposed project
or program for the
purpose of informing
the public and
obtaining input.
Ingress The entrance
points on a
highway which have
access control.
Inner Cordon A
line established for
the purpose of
obtaining origin and destination information
about vehicle trips
within the internal area.
Roadside interview stations
are located along the
inner cordon where the
cordon intersects major roadways.
Interchange A system of
interconnecting roadways providing
for the free movement
of traffic between
two or more
roadways on different levels.
For example, three
types of interchanges are:
cloverleaf, diamond and
directional.Variations of these
basic types are
possible.
Interdisciplinary
Approach Involving
a variety of
professions in solving
a particular problem.
Intermittent Resurfacing
This is patching
in certain locations
where road conditions warrant,
(anywhere from a few feet to one-half mile) and is
less costly than
redoing an entire
highway surface.
Intermodal Transfer Change
from one type
of carrier to
another.(e.g. truck to airplane)
Internal Cordon The internal
cordon encloses an
area within the
study area, such as the central
business district.
Internal Survey The phase
of the survey
in which traffic
data are obtained by
interviewing residents of
selected dwelling units throughout the
entire survey area
and interviewing the owners
or operators of
a a representative sample
of all taxicabs and
trucks registered in the survey
area.
Internal Trip A trip with
both origin and destination within
the survey area.
Interstate A divided arterial
highway for through
traffic with full control
of access and ingress
and egress only
at interchanges. The interstates
are a federally
designated national system of
interstate and defense
highways.
Inversion A weather term
which explains what
happens when, somewhere above
the ground, the
thermal gradient is reversed,
thus not allowing
the air to
mix as much
as normal. An inversion
lowers the depth
to which thermal mixing (warm
air rising) takes place.
This is of
particular concern because increased pollution
can result during periods of
inversion.
Island (Raised
or Painted) Used
to separate vehicular
traffic traveling in opposite
directions. (see also Traffic
Island)
Jacking and
Cribbing Underground construction
of tunnels, conduits
and structures require the
excavations be kept
from caving in by
the use of
a supporting framework.
Land Use The
functions for which
various land areas
are used or are
planned to be
used, such as:
agriculture, housing, education, cultural
recreations, religious, industrial
and commercial uses.
Land Use
Forecast An
estimate of the
number of acres
in specific use by
a specific date
at a particular
location.
Lane Mile One
mile of
a two-lane highway
equals two lane
miles.Therefore, if there
are four “lane
miles” of two-lane,
there are eight actual
miles to maintain.
Lateral Obstacle
Clearance An
area relatively flat
and free of
obstacles beyond the edge
of the travel
way for the
recovery of out-of-control
vehicles.
Level of
Project An
alphabetical designation assigned
to a project
which indicates factors such
as type of
project, degree of complexity
and extent of
social, economic and environmental study
required.
Level of
Service The
term used to
indicate the quality
of service provided by
a facility under
a given set
of operating conditions.These conditions
include speed, travel
time, traffic interruptions,
freedom to maneuver, safety, driving comfort and convenience,
and operating costs.
Level Review
Committee The
group established in
the Action Plan
to review all proposed
projects, flowing systems
planning,to determine their level.
The established level
serves as a guideline for
the type of
study which is
needed and procedures for
the project.
Limited Access
Highway Every highway, street or roadway which
owners or occupants of
adjacent land and
other persons have
no legal right of
access to and from
the highway except
at such points and
in such manner
as determined by the
public authority having
jurisdiction over said
roadway.
Link “Connecting Link”
is a section
of state marked
and/or maintained road which
forms a distance-saving connection between numbered
highways. A link extends between
and junctions with two
other state highways.
Normally, a connecting link
is short in
length.
Local Road
A street or road
primarily for access
to residence, business, or
other abutting property.
Local Trip A trip passing
through the cordon
line which either originated or
ended within the
survey area.
Machine Count A
traffic count made
by a vehicle
recording traffic counting machine
on tape with
a vehicle detector
at a specific location
on a highway.
Maintenance The preserving
and keeping of
each type of
roadway, roadside,
structure, and facility
as nearly as
possible in its original
condition as constructed,
or as later
improved.
Maintenance and
Operating Costs Cost
of keeping the
road in operating condition. (e.g. repair of
chuck holes, mowing,
snow removal)
Major Street
or Major Highway An arterial
highway with intersections
at grade and direct
access to abutting
property, and on which
geometric design and traffic control
measures are used to
expedite the safe
movement of through
traffic.
Manual Count A
traffic count made
by stationing a person at
a specific location on
a highway and
recording traffic by
tally sheet, hand counters,
or other non-automatic
devices.
Mapping A method by
which any number
of different factors
can be examined individually
and in combination
in relation to one
common objective. (e.g. the
best route for
a highway after consideration
of the factors)
Market Value The
highest price for
which property can
be sold in the
open market by
a willing seller
to a willing
purchaser,neither acting with
compulsion and both
exercising reasonable judgment.
Mean Trip Time Travel
time determined by
compiling the elapsed
trip times for all
trips in a particular movement
and dividing the total
by number of
trips. This technique
is used to
find a weighted travel
time for trips
between a work
zone cluster and each
ring-corridor segment in
which the workers live.
Mean trip time
is usually determined
for each mode.
Median The portion
of a divided
highway separating the
traveled ways for traffic
in opposite directions.
Median Lane A speed-change lane
within the median
to accommodate left-turning vehicles.
Meteorological Conditions
Weather conditions; temperature,
wind speed and direction,
and thermal gradient;
used to define
the mixing layer depth
(height of inversion).
Minimum Design
Standards Adopted
by the Board
of Public Roads Classification and Standards. These
standards ensure that each
road segment can
handle the traffic
pattern and volume it
is expected to
carry.
Mobilization The Department
typically reimburses the
contractor when completed portions
of work are
performed. Contractors therefore must
find financing to
help start a
new project. The pay item mobilization
was created a
few years ago to help
the contractor with
these early start-up
costs.
Modal Split The
division of person
trips between mass
and private transportation.
Mode of Travel Means
of travel such
as auto driver,
vehicle passenger, mass transit
passenger, or pedestrian.
Model A system of
data presented in
a mathematical format (as in
traffic model).
Mulch A protective covering
(e.g. native hay or grain straw) spread
on the
ground to reduce
evaporation, maintain even soil
temperature, and prevent
erosion.
Multiple Correlation
Correlation involving one
dependent variable and
two or more independent
variables.
Multiple Regression A
trend line involving
one dependent variable
and two or more
independent variables.
Multiple Use
of Space Projects
in which usage
by the public
or some other agency
can be made
of that space
which was acquired for
the development of
a highway project.
This can involve use
under an existing
overhead structure, the use of
air space above the roadway,
usage alongside the highway,
or a combination
of these and
could be developed either
at the time
of construction or later.
NSI Nebraska Serviceability Index. The value
is a numerical index representing
the observed surface
distress on the pavement
based on a
scale of 0
to 100, with
0 being the worst
and 100 the
best condition.
National Highway
System (NHS) A system
of roads nation-wide
that includes the Interstate
highway system as
well as other roads
important to the nation’s economy,
defense, and mobility.
Almost 160,955 miles
of road, 3,000
of which are in
the state of
Nebraska, have been
designated as being on
the NHS.
Native Grasses
Those grasses which
are common to
the area in
which they are planted.
Negative Declaration A
written statement that
the probable effects
of a project on
the environment will
be minimal.
Neighborhood A primary informal
group consisting of
all persons who live
in local proximity.
Often considered to
be the locality served by
an elementary school
or neighborhood convenience
shopping center. Neighborhoods form the more
or less cohesive
cells of a
larger community.
Neoprene Expansion
Joint The
transverse joint found
at the ends
of bridge deck slabs
is sometimes filled
with a prefabricated black rubberized
material called neoprene
expansion joint. The rubber
expands and contracts
with the broad
range of Nebraska temperatures. Node A specific point
on a study system network
where two or more
links intersect and
where a choice
of travel routing is
possible. A node may coincide
with a zone
centroid and may be
used for the
purpose of describing
the network.
Noise Level The
degree of undesired
sound which affects
the auditory senses. Allowable
noise levels have
been defined in Federal
Highway Administration Policy
and Procedure Memorandum.
Noise Sensitive
Areas Those
areas adjacent to
a proposed improvement which would
be adversely affected
by excessive noise levels. (e.g. hospitals, schools, churches)
Obligation
Authority The
actual amount of
federal funds which
are available for expenditure
within a fiscal
year.
One-and Six-Year
Plans The
immediate one-year construction
to be done in
the current fiscal
year and the
proposed highway construction objectives
for the next
five fiscal years. These
plans are updated
annually to include
the next fiscal year. These
plans are prepared
by the Department.
Operating Speed The highest
overall speed at which a
driver can travel
on a given highway
under favorable weather
conditions and under prevailing
traffic conditions without
at any time exceeding the
safe speed as
determined by the
design speed on a
section-by-section basis.
Opportunity Model A
mathematical formula based
on the premise
that the probability of
a trip originating
in one zone
will find a destination
in another zone
is proportional to
the possible trip destinations
in the other zone, and
to the number
of trip origins that
have not previously
found a destination.
Orientation Meeting
Informal presentation of information by the
Department relating to a proposed project
or program for the
purpose of obtaining
the public’s views.
These are the first
type of meetings
held with the
public before a corridor
study is begun.
The public is
informed about the area
of interest, the
procedures and techniques
to be followed, and
an estimated timetable
for the project.
Origin The zone
in which a
trip begins.
Origin-Destination Studies
Trip data is
obtained from vehicle
drivers as to where they
started, where they
are going, and
the purpose of their
trip. This data
helps the Department
to forecast traffic patterns.
Over-All Speed
Total distance divided
by total time,
including all delays.
Overpass A grade separation
where the highway
passes over a highway
or railroad. (See
Grade Separation).P.R. 1 The
initial federal form submitted
to the FHWA which describes project
location, type of
construction proposed, estimated costs
of engineering, right-of-way
and construction. This document
serves as a
request for funds to
proceed with project
development.
PSI Present Serviceability
Index represents the
ride quality of a
pavement based on
a scale of 0
to 5, with
0 being the worst
condition and 5
the best.
Paleontology A science
dealing with the
life of past
geological periods as known
from fossil remains.
PAM Pozzolanic Aggregate Mixture
Parking Lane An
auxiliary lane primarily
for the parking
of vehicles.
Partial Taking The
acquisition of a
portion of a
parcel of property.
Pavement The part
of a roadway
having a constructed
surface for the facilitation
of vehicular movement.
Pavement Fabric These are
prefabricated sheets of
steel mesh that
are occasionally placed into
new concrete pavements.
Pavement Life The
design life for a roadway
is 50 years.
Pavement Marking The lane
lines or symbols
painted on pavement surfaces. Marking
can be done with several
different types of materials.
Pavement/Pothole Patching
When the pavement
begins to deteriorate due to
the influences of the environment
and traffic,holes, ruts
and cracks are usually localized
at existing pavement joints.
The repair of this type
of failure consists of
sawing out, removing
and replacing the
material with new Portland
cement concrete or
bituminous concrete.
Peak Hour
That one-hour period
during which the
maximum amount of travel
occurs. Generally, there
is a morning
peak and an afternoon
peak and traffic
assignments may be
made for each period,
if desired.
Pedestrian Any person
afoot.
Pedestrian Crossings
Designated crossings where
pedestrians may safely cross
a busy highway
or roadway.
Performance Graded
Binder A performance graded
binder came about with
the developments of
Superpave. The superpave system incorporates
performance based asphalt
materials characterization
with the mix
design and environmental conditions to
improve performance by
controlling rutting, low temperature
cracking, and fatigue
cracking.
Permanent Seeding
Planting of ground
cover after completion
of the improvement. These
grasses and legumes
will be of a lasting nature
to insure continued
control of soil
erosion.
Planning and
Research Funds Federal
funds are available
for research on all
phases of highway
construction, modernization,development,
design maintenance, safety, financing, and traffic conditions.
The research may
be conducted by government
agencies or private
groups. One and
one-half percent of each
state’s federal-Aid apportionment
is reserved to be
used exclusively for
these purposes.
Federal funds made available
for planning and
research projects must be matched
by
the state in
accordance with prescribed
ratios unless FHWA determines that
no matching funds are
required.
Planning Study
Report A Department document
which is prepared
at the beginning of
a project. This basic
document will contain a location map,
type of improvement,
documentation of the supporting
needs for the
project, statement as to whether any
significant environmental impact
is anticipated, statement of
alternatives, and a
list of study areas
examined. This document
will be circulated
within the Department, to
other agencies, and
to the public
for their input.
Planting Easement An easement
for reshaping roadside
areas and establishing, maintaining
and controlling plant
growth thereon.
Policy and
Procedure Memorandum Form
used by the
Federal Highway Administration to inform agencies
of the FHWA’s interpretations and
applications of federal
statutes dealing with highway
and transportation matters.
Population Estimate
Estimating current population
on the basis
of demographic and economic
data.
Population Forecast
Estimating future population
on the basis
of demographic and economic
data.
Possible Capacity The maximum
number of vehicles
that can pass a
given point on
a lane or roadway during
one hour under prevailing roadway
and traffic conditions.
Pozzolanic This is
a mixture of
aggregate, water and
a cementing agent that
consists of lime
and fly ash
to create a
durable road surface.
Practical Capacity The maximum
number of vehicles
that can pass a
given point on
a lane or
roadway during one hour
under the prevailing roadway
and traffic conditions
without unreasonable delay or
restrict to the
driver’s freedom to maneuver.
Precast Concrete
Bridge Slab A new
concrete bridge slab
can be constructed by
the use of either cast-in-place
reinforced concrete, or by
the use of
precast concrete deck segments
manufactured off site,
transported to the
job, and lifted up
and set on
the bridge piers.
These segments are then
tied together with
steel bolts and
the joints filled with
a cement mortar.
Depending upon the
type of design, these
precast concrete bridge
slabs will be
either driven upon directly
or first surfaced
with a bituminous
concrete surface.
Preliminary Engineering
Costs Includes all the survey, design, material
exploration, and plan
preparation up to
letting the project for
construction.
Priority Commercial Systems A continuous network
of routes, within
the State of Nebraska,
which are designed
to carry higher traffic volumes,
especially larger volumes
of commercial vehicles. This
system, which includes
the rural express- way
system, includes about
3,300 miles of
road. It directly serves all
of the first
class (5,001-100,00 population)
and larger cities; directly
serves 80 of
the 113 second
cities (800-5,000
population), and comes
within 10 miles
of 23 second class cities.
Program (noun) A priority
listing of projects,
usually for a
defined period of time (e.g. 6
years, 20 years). Programs are subject
to continued review before
they are established
as projects by the
Department.
Program (verb) To establish
and execute procedures.
In fiscal accounting - to allocate
funds for specific
projects.
Program Balance The amount
of money left out of
the Federal apportionment
which has not
been set aside
for particular projects.Project The specific
section of the highway together
with all appurtenances and
construction to be
performed thereon under the
contract.
Project Agreement An
agreement between the
federal government and the
state which specifies
the federal funds
to be used for a
particular project. The
form is necessary
for reimbursement from FHWA. (See Transfer of Federal Funds to State)
Project Number A
number with a
letter prefix which
is assigned to a project to
identify it on
correspondence, documents and plans.
The number indicates
location and funding. Public, Mass or Rapid Transit (a)
Vehicles used to
convey people from one
place to another.
(b) The system
or company which owns
such vehicles.
Radial Highway An arterial
highway leading to
or from an
urban center.
Railroad Grade
Crossing The
general area where
a highway and a railroad cross
at the same
level, within which
are included the railroad,
roadway, and roadside
facilities for traffic traversing that
area.
Raised Island
That portion of
the roadway which
is raised above
the travel-way by means
of a curb
to separate traffic.
Ramp A connecting roadway
between two intersecting
highways at a highway
separation.
Random Selection
Every combination of
samples of a
given size from a
population, no matter
how small or
how large, has an
equal chance of
being selected.
Rate of
Change The
proportional and consistent
change in the
size of a variable
from one period
to the next.
Recreation Road A roadway
which is not
part of the
state highway system but
which has been
developed and improved
by money from the
State Recreation Road
Fund in accordance
with Section 39-1390 of
the State Statutes.
Reflective Crack
Control Treatment A method
used to retard
the reflective cracking into
or thru the
new asphalt surface;fabric, heavy
overlay or other
strategies are used.
Regional Growth
Model A land-use model used to
estimate growth and future
land-use patterns.
Regional Planning
Agency An area-wide A-95 Review Agency (See A-95 Review Agency). There
is presently one such agency
in Nebraska located in
the southeast portion.
The counties which form
this agency are:
Nemaha, Johnson, Pawnee, and
Richardson.
Registration The registration
certificate or certificates
and registration plates issued
under the laws of this
State pertaining to the
registration of vehicles.
Reinforcement Bars Concrete
pavements and structures
can be designed to
withstand most types
of loading if
the concrete is reinforced
with steel bars. These bars
are called reinforcement bars.
Relocation
Assistance Program Program
for providing advice
and assistance to persons,
businesses, etc. which
have to be relocated
due to highway
construction.
Remainder The portion
of the tract
of land retained
by the owner after
a part of
such tract of
land has been
acquired.
Remnant A remainder so
small or irregular that
it usually has
little or no economic
value to the
owner.
Retaining Wall Structure used
to contain an embankment,
also used on a backslope.
Right of
Immediate Possession The
right to occupy
property for highway purposes, after
preliminary steps for
acquisition have been taken
and before final
settlement.
Right of
Survey Entry The
right to enter property temporarily
to make surveys and
investigations for proposed
highway improvements.
Right-of-Way Land
acquired by purchase,
gift or eminent
domain in order to
build and maintain
a public road.
Right-of-Way
Appraisal A determination of the market
value of property including damages,
if any, as of a
specified date, resulting from an
analysis of facts.
Right-of-Way
Estimate An
approximation of the
market value of
property including damages, if
any, in advance
of an appraisal.
Right-of-Way Strip
Map A plan
of highway improvement
showing its relationship to
adjacent property, the
parcels or portions thereof, needed
for highway purposes,
and other pertinent information.
Riparian Relating
to, living, or
located on a
bank of a natural
watercourse (as a
river) or sometimes of
a lake or a tidewater.
Riparian Right
The rights of an owner
of water-fronting lands
in the bed, banks,
accretions, water, access,
moorage, and related items.
Riprap When the
Department constructs an
embankment adjacent to a
stream or lake,
the bank is
lined with broken concrete or
limestone rock to
prevent erosion.
Riverine Living
or situated on
the banks of
a river.
Road User
Benefits The
advantages, privileges or
savings that accrue
to drivers or owners
through the use
of one highway
facility as compared with
the use of
another. Benefits are measured
in terms of
the decrease in
road user costs and
the increase in
road user services.
Road User
Costs Vehicular
operating costs, usually
expressed in cents per vehicle mile,
covering all items
involved in vehicle ownership and
operation. The value
of time is
included as one of the
items of cost.
Road User
Services Advantages or
privileges accruing to
the vehicle driver or owner
through features of safety, comfort,convenience, etc.
In some cases
these can be
evaluated in cents per
vehicle mile.
Roadside Control The public
regulation of the roadside
to improve highway safety, expedite
the free flow
of traffic, safeguard
present and future highway
investment, conserve abutting
property values, or preserve
the attractiveness of
the landscape.
Roadside Development
Those items necessary
to complete the
highway which provide for
the preservation of
landscape materials and features;
the rehabilitation and
protection against erosion of
all areas disturbed
by construction through seeding, sodding,
mulching and the
placing of other ground
covers, trees and
shrubs, and such
suitable planting and other
improvements as may
increase the effectiveness and
enhance the appearance
of the highway.
Roadside Zoning The application
of zoning for
roadside control.
Roadway The portion
of a highway, including
shoulders, for vehicular use.
Roadway Cuts Segments
of roadway lower
than the surrounding
ground.
Roadway Embankment A
raised structure of
soil, soil-aggregate, sand or rock.
Rural Area An area
whose character is rural in
nature and which may
include towns of
less than 5,000
population.
Safety Features
Highway features which
provide for safe
travel. These include flat
slopes, no hazardous
obstacles within thirty feet
of the driving
lanes, breakaway sign
supports, and safety beams
and cable guards.
Safety Zone
The area
or space officially set
apart within a
roadway for the exclusive use of pedestrians
and which is protected
or is so
marked or indicated by
adequate signs as to
be plainly visible
at all times
while set apart
as a safety zone.
Salvage Saving
different materials from
projects where existing surfacing and
structures are removed
and using these
in other construction.
Sawing Concrete
Pavement When
patching a failed
area of existing pavement the
contractor is required
to make a
full depth saw cut
around the perimeter
of the patch
so that the segment
can be dislodged
and removed. Also
done to control cracking
in concrete.
Scenic Easement An easement
for conservation and
development of roadside views
and natural features.
Scheduling The process
of developing a plan of
operations to carry out
the program. The
process first involves
breaking down projects into
activities, setting starting
and ending times for
those activities, determining
the resources required
to
perform the
work, then adjusting
the times as
necessary to balance the
resource requirements.
Screening The use
of any vegetative
planting, fencing, ornamental wall of
masonry, or other
architectural treatment, earthen embankment, or
a combination of
any of these
which will effectively hide from view
any undesirable areas, especially junkyards,
from the main
traveled way.
Screen Line
An imaginary line,
usually along physical
barriers such as rivers
or railroad tracks
splitting the study
area into two parts. Traffic counts (and possibly
interviews) are conducted along this
line, and the
crossings are compared
to those calculated from
the interview data
as a check of survey accuracy.
Seal Coat
An existing county
or township road,
or state highway can be rehabilitated
or given a
new wearing surface
by spraying it with
a liquid asphalt
followed by a
uniform sprinkling of aggregate.
This procedure is
called a seal coat
or chip and seal.
Seasonal Changes Changes brought
about by seasons. Section 4(f)
Land Any publicly
owned parks, recreation
areas, historic sites, or
wildlife or waterflow
refuges of national,
state, or local significance as
determined by federal,
state or local officials having
jurisdiction over such
lands.
Sector A combination of
traffic zones which
presents a more meaningful tabulation
of traffic data.
Sediment Basin
Structure in which
water moves slowly enough
for suspended particles to
settle.
Severance Damages
Loss in value
of the remainder
of a parcel
resulting from an acquisition.
(Sometimes called Indirect
Damages)
Shared Roadway
Facilities officially
designated and marked
as bicycle routes but
also open to motor vehicle
travel with no provision
for physical separation
of the two
types of vehicles.
Shoo-fly Localized
detour adjacent to
the construction.
Shoulder The portion
of the roadway
adjacent to the
traveled way for accommodation
of stopped vehicles,
for emergency use, and
for lateral support
of the base
and surface courses. On
secondary roadways the
shoulder usually consists of
turf. On heavily traveled
roads the shoulder is usually a
bituminous mixture or
concrete.
Sight Distance
The line of
sight available to
the driver to
see another car for passing
sight distance or
to see a
fixed object for stopping sight
distance.
Sight Line
Easement An
easement for maintaining
or improving the sight distance.
Signing Visual
method of providing
the vehicle driver
with guide, warning and
regulatory information along
a highway.
Simulate To
reproduce synthetically.
(e.g., to simulate
trip distribution)
Slope Drains
The drainage structures
used to prevent
water erosion damage to
slopes.
Slope Easement An easement
for cuts or
fills.
Social Costs
Costs that are
not included in
the usual calculations concerning engineering,
construction and right-of-way costs.
Social and
Economic Generators Those
social and economic
activities which generate traffic.
Socio-Economic Factors
These are used
to assess the
effect of the highway
on the human
environment. Some include: population trends
and growth, economic
activity, transportation
facilities, wildlife, scenic
and wildlife, scenic and
recreational facilities, historical
resources, aesthetics, social service
facilities, land use,
and national defense.
Soil Erosion The
wearing away of
soil by the
action of water,
wind,or glacial ice.
Space Utility
Added value gained
by movement of
a product from
one place to another,
e.g. wheat increases
in value as it moves from
farm to market.
Special Excavation On a
roadway contract that runs
through a city,
there are numerous miscellaneous
items that need
to be removed (curb, sidewalk, driveways,
earth, etc.). These items are
combined under the
item Special Excavation.
Specifications The
standard specifications, supplemental
specifications, special
provisions, and all written or
printed agreements and instructions
pertaining to the
method and manner
of performing the work
or to the quantities
and qualities of the
materials to be
furnished under the
contract.
Speed-change Lane An
auxiliary lane including
tapered areas, primarily for
the acceleration or
deceleration of vehicles
entering or leaving the through
traffic lanes.
Spurs A roadway on
the state highway
system which radiates from
another numbered route
on the state
highway system. The principal
characteristic is that
only one end of the
route junctions with
another highway route.
Stability Classes A
weather term which
denotes classes A through F derived
from meteorological data
that determine the severity
of air pollution
potential. Class A - very
much turbulent mixing of
air; class F
- very little
mixing,pollution stays where
it is emitted.
Standard Metropolitan
Statistical Area (SMSA) Area or
SMSA: An integrated economic and
social unit with
a large population nucleus. Each
SMSA contains: (a) one central city of
50,000 or (b)
two cities with
contiguous boundaries, for economic
and social purposes,
a single community with a
combined population of
50,000, the smaller of
which must have
a population of
15,000. It includes counties and
may cross state
lines.
State Highway
Agency The
agency with the
primary responsibility for initiating and
carrying forward the
planning, design and construction of highway. In Nebraska this
is the Department of Roads
(DOR).
State Highway
System Roads,
streets and highways
provided for in the
Nebraska Highway and
Bridge Law which
form the group of
transportation lines for
which the Department
will have primary responsibility. The system
shall include, but
not be limited to, right-of-way, connecting links, drainage facilities, and
bridge appurtenances, easements
and structures used in
conjunction with such
roads, streets, and highways.
State User
Funds Revenue
from state tax on motor
fuel, motor vehicles registration and
motor carrier fees.
Not all of
these go into the
State Road Fund
- some are
withheld for administrative costs
and other state,
county, or municipal costs. Other
sources include property
rental, sale of surplus
property and equipment,
sale of sign
permits and interest on
invested funds.
Statewide Traffic
Assignment Model A computerized procedure
for simulating present and/or
future vehicular trips
on an existing or
proposed network of
highways on a
statewide basis.
Station (Survey) A numerical designation
for points on
a project centerline which denote
the distance of that point
from another point on
the project.
Station (Traffic) A location at
the external cordon
line where driver interviews are
conducted. Also vehicle
count station or vehicle
weight station.
Steel Bascule
Bridge A kind
of drawbridge counter-weighted so
that it can be raised
and lowered easily.
Storage Lane An
auxiliary lane, primarily
to allow those
vehicles which turn to
wait for through
traffic to proceed across
the intersection.
Study Area The area
encircled by the external cordon. (See
External Cordon)
Surfacing Material
used to construct the
roadway. There are four types: Asphalt, Bituminous, Concrete,
Gravel.
Survey Period
That time during
which the external
origin and destination survey is
conducted. The survey
period begins the
day that the first
interview station is
operated up to and
including the day
of the last
interview station.
Systematic Interdisciplinary The
involvement of persons,
from professions in addition
to engineering, in
the planning,location and
design phases of
project development. The purpose
of this involvement
is to approach
and insure adequate consideration
of the social,
environmental and economic effects
of highway programs.
Systems Planning The study
of transportation needs
in a particular
area. The area studied
may be an
urban area, a
DOR field district or
the entire State.
The result of
systems planning may be
a recommendation of
improvements or additions to
the existing transportation system,
or the creation
of new modes.
Systems Planning
Phase The
preliminary work to study need and establish priorities.
Terminus The origin
or destination of a trip.
Also the location
of the starting point
and ending point
of a highway
construction project.
Terrain The physical
features of a
tract of land.
Thermal Gradient A
weather term which
describes the change
in temperature with a
change in altitude
(height above ground).
Normally temperature decrease
with increasing altitude. (See
Inversion)
Through Street
or Through Highway
Every highway or
portion thereof at the
entrance to which
vehicular traffic from
intersecting highways is required
to stop or
yield before entering
or crossing and where appropriate
signs are erected
as provided by law,
unless entry or
crossing is made
on the proper indication
of a traffic-control signal.
Through Trip A trip having
both origin and
destination outside the Survey
Area, passing completely
through the area
and crossing the cordon
line twice.
Time Cost Travel time by
car or transit (door-to-door), converted
to cost values (cents per minute) so that
time costs may be
combined with other
items of cost.
Topography
Representation on
maps or charts
depicting natural and man-made
features of an
area or region.
Tourism Pleasure
trips usually of longer
than local distance. Traffic All types
of conveyances, together
with their load, whether
singly or as
a whole, as
well as pedestrians, while using
any roadway for the purpose
of transportation or travel.
Traffic Assignment A method
of distributing trips
on a road
network or on a
theoretical network to illustrate how
various sets of physical
conditions and travel characteristics would
affect the traffic flow
pattern, for instance,
speed, distances, etc.
Traffic Control
Device Any
sign, signal, marking
or installation placed or erected under public authority, for
the purpose of regulating, warning, informing
or guiding traffic.
Traffic Count A
count of
total vehicular traffic
passing a given
point on a highway
during a specified
time period. This
might be a manual
or machine count.
Traffic Demands The number
of vehicles desiring
to use a
particular route.
Traffic Flow
The movement of
vehicles on a
highway system or
on a single route.
Traffic Forecasting
Estimating future traffic
patterns on the
basis of known transportation variables.
Traffic Island
An island provided
in a roadway
to separate or
direct streams of traffic; includes
both divisional and channelizing islands.
Traffic Lane
The portion of
the traveled way for movement
of a single line
of vehicles.
Traffic Marking A
traffic control device
consisting of line,
patterns, or colors on the pavement,
curbs, or other
objects within or adjacent
to the roadway,
or words or
symbols on the pavement.
Traffic Sign A traffic
control device mounted
on a fixed
or portable support which
conveys a specific
message by means
of words or symbols,
and is officially
erected for the
purpose of regulating, warning,
or guiding traffic.
Traffic Signal A
power-operated traffic control device
by which traffic
is regulated, warned, or
alternately directed to
take specific actions.
Traffic Volume The
amount of traffic
on a particular
route.
Traffic Zone
A subdivision of the
study area established
for the purpose of
tabulating, analyzing, and
projecting future vehicular travel.
Transfer of
Federal Funds
to State Federal-aid for
highways is received by
the state in
the form of
reimbursement for work already
done and paid
for by the
state. The state
may claim the federal
share of the cost of
work in the
form of monthly progress payments. All federal-aid highway projects must
be approved in
advance by FHWA. A project agreement
is required before
a state mayreceive
any reimbursement from
the FHWA.
Travel Time The time
of travel, including
stops and delays,
except those off the
traveled way.
Traveled Way The
portion of the
roadway for the
movement of vehicles, exclusive of
shoulders and auxiliary
lanes.
Trench Backfill Soil or
sand used to
backfill storm sewer
trenches.
Trip A one-direction movement
of a vehicle
which begins at the
origin at the
start time, ends
at the destination
at the arrival time,
and conducted for a specific
purpose.
Trip Generation
Commonly used to
describe the number
of trips starting or
ending in a
particular area in
relation to the
land use or socio-economic characteristics of
that area. A study of trip
generation does not
attempt to describe
all of the characteristics of
trips, direction, length,
or duration, but simply
to identify and
quantify the trip
ends in a
particular area/unit.
Tubular Thrie
Beam Retrofit Rail Several
of the bridges
constructed years ago were
provided with side
rails that were designed
to standards that
have since been
upgraded to better redirect errant
vehicles. In front
of the old
rail a new metal beam
retrofit rail is
constructed, consisting of
three corrugations similar to
a guard rail,
and will redirect most
vehicles.
Unchannelized Intersection An
at-grade intersection without
islands for directing traffic
into definite paths.
Underdrains The pipe
that is put into the
trench next to
the highway (a multi-lane divided
highway). It is backfilled
with porous
sand which
lowers the water
table and makes
the grade of the
highway more stable.
Underpass A grade separation
where the highway
passes under an intersecting highway
or railroad. (See Grade Separation)
Unrestricted Access Crossings
of the highway
are permitted at-grade along the
entire length.
Urban Area An area
whose character is
urban in nature
and which may include
towns of more
than 5,000 population.
Vehicle Every device,
in, upon, or by which
any person or property
is or may
be transported or
drawn upon a highway,
excepting devices moved
by human power
or used exclusively upon
stationary rails or
tracks.
Vehicle Miles
Normally obtained by
multiplying the average
daily traffic by 365
and by multiplying
the mileage of
road to which the
average daily traffic
is applicable.
Vehicles Per Day
or VPD Number
of vehicles that
pass a particular
point on the road
during a period
of 24 consecutive
hours.
Vertical Curve A
smooth transition between
two sloping grade
lines; a hill or valley.
Vertical Curve (of Highway) A
curve on
the longitudinal profile
of a road to
provide for change
of gradient.
Viaduct A bridge for
carrying a road over a
valley, another road, or
railroad.
Visibility The farthest
object that can
be observed. In
daylight landmarks are used;
but at night
unfocused lights serve as
reference points.
Visual Impact
Appearance of the
roadway and appurtenances
to an observer.
VMT Vehicle
miles of travel.
Volume The number
of vehicles that
pass over a
given section of a
lane or roadway
during a time
period of one
hour or more. Volume
can be expressed
in terms of
daily traffic or annual traffic,
as well as on an
hourly basis.
Water Pollution The addition
of harmful or objectionable material
to water in concentrations or
in sufficient quantities
to result in measurable
degradation of water
quality.
Waterproofing Membrane
System A combination liquid
asphalt and fabric placed
on top of
the concrete bridge
deck prior to the
placement of the
bituminous wearing surface.
On certain types of
bridge decks, a bituminous wearing
surface is specified on
top of the
concrete deck.
Watershed The area
contained within a divide above
a specific point on
a stream.
Weekday Traffic The
number of vehicles
that passes a
given point on the
road during a
consecutive 24-hour period
from Monday to Friday, inclusive.
Weight Related
Cost The
extra cost of highway
construction brought about by
building capacity for
heavy loads.
Wetland Those areas
that are inundated
or saturated by
surface or ground water at
a frequency and
duration sufficient to support,
and that under
normal circumstances do
support, a prevalence of
vegetation typically adapted
for life in saturated
soil conditions. Wetlands
generally include swamps, marshes,
bogs, and similar
areas.
Wildlife Habitat The environmental
conditions of a
specific place that
is occupied by a
specific species of
wildlife.
Wind Rose Historical
data for a specific time
period that shows cumulative wind
directions and speeds.
Such a diagram shows
what direction the
wind blows from
for a certain percentage of
the time.
Zone A portion of
the study area,
delineated as such
for particular land use
and traffic analysis
purposes. There may be
two types of
zones used in
the traffic assignment process: (a)
Survey zone - A subdivision of
the study area which
is used during
the data collection
phase of the study. (b)
Traffic assignment zone -
A subdivision of the study
area represented by a centroid.
Zone Centroid A
point of
trip origin or
destination.
Zoning The division
of an area
into districts and
the public regulation of
the character and
intensity of land
use and improvements thereon.
About Author:
I am Thomas Britto here to share my experiences in the civil engineering field to all my readers.Today many students are struggling to buy books at high prices. So I decided to start a blog and share my experience and knowledge with all my readers.
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