Glossaries

Definitions: J - L

 

L10 – A sound level that is exceeded 10 percent of the time for the period under consideration.  This value is an indicator of both the magnitude and frequency of occurrence of the loudest noise events.

Lane Balance – The condition where the number of lanes leaving a diverge is one more than the number of lanes approaching the diverge.

Lanes –

Acceleration Lane - A speed-change lane, including tapered areas, for the purpose of enabling a vehicle entering the roadway to increase its speed to a rate at which it can more safely merge with through traffic. Also called an “accel lane" (GDOT Driveway Manual, 2004).

Auxiliary Lane – The portion of the roadway adjoining the traveled way to help facilitate traffic movements: by providing for parking, speed change, turning, storage for turning, weaving, truck climbing, or for other purposes. 

Center Turn Lane – A lane within the median to accommodate left-turning vehicles. 

Deceleration Lane – A speed-change lane, including tapered areas, for the purpose of enabling a vehicle that is making an exit turn from a roadway to slow to a safe turning speed after it has left the mainstream of faster-moving traffic. Also called a “decel lane"; it denotes a right turn lane or a left turn lane into a development (GDOT Driveway Manual, 2004).

Left Turn Lane – A speed-change lane within the median to accommodate left turning vehicles.

Inside Lane - On a multi-lane highway the extreme left hand traffic lane, in the direction of traffic flow, of those lanes available for traffic moving in one direction.

Parking Lane – An auxiliary lane primarily for the parking of vehicles. 

Passing Lane –

(1) A section of two-lane, two-directional road where sufficient clear sight distance exists to allow a safe passing maneuver to be performed.

(2)  An additional (third) lane that has been added to a two-lane roadway specifically for passing.

Turn Lane – A traffic lane within the normal surfaced width of a roadway, or an auxiliary lane adjacent to or within a median, reserved for vehicles turning left or right at an intersection. 

Traffic Lane – The portion of the traveled way for the movement of a single line of vehicles in one direction. 

Letting – The date GDOT opens sealed bids from prospective contractors.

Level of Service – A qualitative rating of a road’s effectiveness relative to the service it renders to its users (from A-best to F-worst). LOS is measured in terms of a number of factors, such as operating speed, travel time, traffic interruptions, freedom to maneuver and pass, driving safety, comfort, and convenience.

Lighting –

High Mast Roadway Lighting– Illumination of a large area by means of a group of luminaires designed to be mounted in fixed orientation at the top of a high mast, generally 80-ft. or higher (AASHTO Roadway Lighting Design Guide, 2005).

Pedestrian Lighting – Illumination of public sidewalks for pedestrian traffic generally not within rights-of-way for vehicular traffic roadways.  Included are skywalks (pedestrian overpasses), subwalks (pedestrian tunnels), walkways giving access to park or block interiors and crossings near centers of long blocks (AASHTO Roadway Lighting Design Guide, 2005).

Roadway Lighting - Illumination of roadways by means of fixed luminaires in order to reduce driver conflict with other vehicles and pedestrians

Limited Access Facility – A street or highway to which owner or occupants abutting land have little or no right of access.

Local Road – Functional classification that consists of all roads not defined as arterials or collectors; primarily provides access to land with little or no through movement. 

Longitudinal Barrier – A barrier that is intended to safely redirect an errant vehicle away from a roadside or median hazard (CODOT, 2006)

Loop Detector – A traffic monitoring tool that is used to detect the presence of vehicles at an intersection to activate a traffic signal.