Learn the Public Works Terminology

1-percent Annual Chance Flood:
Term used to describe the level of flood that statistically has a 1-percent chance of happening in any year. This was once referred to as the 100-year flood.

85% speed:
The speed of which 85% of all motorists in a study are traveling.

AADT:
Average Annual Daily Traffic

Advanced Detection:
A method of determining traffic flow to allow the traffic signal controller adjust signal timing. This can be either in-pavement loops or camera activated.

Base Flood Elevation:
The elevation shown on the Flood Insurance Rate Map that indicates the water surface elevation resulting from a flood that has a 1 percent chance of equaling or exceeding that level in any given year.

Bi-directional turn lane:
Center lane on some roadways which is used for left turning from either direction.

City Limits:
Properties within the City of Peoria boundaries, as depicted on the plat maps

Controller Cabinet:
The large metal box near a signalized intersection that contains the traffic signal controller.

Close-to-curb plowing:
Plowing and pushing snow back close to the curb or edge of the pavement so all traffic lanes and storm drain inlets are fully cleared.

Easement:
A right held by one property owner to make use of the land of another for a limited purpose.

Encroachment:
A building or portion of building, fixture or obstruction that physically intrudes upon the property of another.  Entry to another's property without right or permission.

FHWA:
Federal Highway Administration

Floodplain:
A floodplain is an area that will be inundated by a flood from a river, creek, ditch, lake, or other water source. The Federal Emergency Management Agency defines floodplain areas based on the flood risk.

Floodway:
The floodway is the regular channel of a river, stream, or other watercourse, plus the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than one foot.

Guide Signs:
Show route designations, destinations, directions, distances, services, points of interest, and other geographical, recreational, or cultural information.

IDOT:
Illinois Department of Transportation

IDS:
Intersection Design Study

ITE:
Institute of Traffic Engineers

Jurisdiction:
The government body that has authority.

Justifying Traffic Control Signals:
An engineering study of traffic conditions, pedestrian conditions, and physical characteristics of the location shall be performed to determine whether installation of a traffic control signal is justified at a particular location.

MUTCD:
Manual on Uniform Traffic Control Devices is recognized as the national standard for all traffic control devices installed on any street, highway or bicycle trail open to public travel.

Oil change:
Preventative maintenance performed on all vehicles to keep them in good working condition.

Pedestrian signals:
Signals used along with traffic signals to denote the safe crossing times for pedestrians. These may be activated either by a pedestrian push button, or automatically recalled.

RCOC:
Remote Controller of Outside Circuits

Regulatory Signs:
Give notice of traffic laws or regulations.

Right-Of-Way:   
A path or route that may lawfully be used, such as land covered by a public road.

RPPP:
Residential Parking Permit Program

School Speed Zone:
Area adjacent to a school with a lower posted speed limit during school days, when children are present. In Peoria school speed zones are 20 mph

Sealcoat:
Over several years time the rays of the sun oxidizes bituminous pavements and makes them brittle. Most local governments apply some type of inexpensive sealcoat process to extend the life of the pavement. The City of Peoria uses a chip-seal process where oil is applied to the pavement and immediately covered with aggregate chips. The oil rejuvenates the pavement and the aggregate cover adds to the wearing surface while enabling traffic to drive on the pavement immediately. The majority of the streets in Peoria are a bituminous surface and are sealcoated on a seven year cycle.

Shared-use path:
A path separated from the roadway which is intended to be used by both bicycles and pedestrians.

Signal Cycle:
The amount of time for a traffic signal to go through all directions of traffic one time.

Signal Phase:
The portion of the signal cycle which is allowed one direction of traffic flow.

Snow Plow:
The blade (large piece of metal) attached to the front of our trucks used for plowing snow. One blade is 42 inches tall, 10 feet wide and weighs 3, 030 pounds. (That’s more than 1 Ton!)

Spot speed study:
A study of roadway speeds captured by radar detector.

Stop line:
A solid white line at the approach of an intersection to indicate where a vehicle must stop.

Study (traffic):
An investigation and evaluation of a traffic concerns (speed, parking, traffic count, collision).

Traffic Control Devices:
Signs, signals, markings and other devices to regulate, warn, or guide traffic, placed on over or adjacent to a street, highway, pedestrian facility, or bikeway by authority of a public agency having jurisdiction.

Traffic Control Signal:
Any highway traffic signal by which traffic is alternately directed to stop and permitted to proceed.

Traffic Counters:
A device to count roadway traffic. These can be seen as little black rectangles on the roadway surface.

Traffic Signals:
The device that shows red, yellow or green lights to control flow of traffic.

Traffic Signal Controller:
A computerized device that controls the traffic signals.

Traffic Signal System:
A method used to control traffic at an intersection, which may include traffic signals, traffic signal controller, controller cabinet and advanced detection. Traffic systems may be either pre-timed or actuated. Pre-timed means that the signal runs according to a predetermined program. Traffic actuated means that the controller utilized advanced detection to adjust the signal timing for maximum efficiency.

Traffic Signal Warrants:
Threshold condition that must be met to determine the need for a traffic signal at an intersection.

Warning Signs:
Give notice of a situation that might not be readily apparent.