Rydal-Meadowbrook Civic Association

Terminology defined by the PA Department of Transportation (PennDOT) in Publication 212: Official Traffic Control Devices: 

85th percentile speed: The speed on a roadway at or below which 85% of the motor vehicles travel.

Engineering and traffic study: An orderly examination or analysis of physical features and traffic conditions on or along a highway, conducted in accordance with this chapter for the purpose of ascertaining the need or lack of need of specific traffic restrictions, and the application of traffic-control devices.

Grade: The up or down slope in the longitudinal direction of the highway, expressed in percent, which is the number of units of change in elevation per 100 units of horizontal distance. An upward slope is a positive grade; a downward slope is a negative grade.

MUTCD: The current edition of the Manual on Uniform Traffic Control Devices, as adopted by the Federal Highway Administration (FHWA), and available on the FHWA website. 

Normal speed limit: The regulatory speed limit or the 85th percentile speed that existed before temporary traffic control was established, for example, prior to the beginning of a work zone.

Stopping sight distance: The length of highway over which a 2-foot high object on the roadway is continuously visible to the driver, with the driver's eye height assumed to be 3.5 feet above the road surface.

Traffic Calming: The combination of primarily physical measures taken to reduce the negative effects of motor vehicle use, alter driver behavior and improve conditions for nonmotorized street users. The primary objectives of traffic calming measures are to reduce speeding and to reduce the volume of cut-through traffic on neighborhood streets. (see Traffic Calming Handbook)

Traffic-control devices: Signs, signals, markings and devices consistent with this chapter placed or erected by authority of a public body or official having jurisdiction, for the purpose of regulating, warning or guiding traffic.

Traffic restriction: A restriction designated by a traffic-control device to regulate the speed, direction, movement, placement or kind of traffic using any highway.

Traffic signal: (i) A power-operated traffic-control device other than a sign, warning light, flashing arrow panel or steady-burn electric lamp. (ii) The term includes traffic-control signals, pedestrian signals, beacons, in-roadway warning lights, lane-use-control signals, movable bridge signals, emergency traffic signals, firehouse warning devices, ramp and highway metering signals and weigh station signals.

Travel lane: (i) A lane of a highway which is used for travel by vehicles. (ii) A lane in which parking is permitted during off-peak hours but is restricted for use as a travel lane during peak hours to obtain greater traffic movement.

Warrant: A description of the threshold conditions to be used in evaluating the potential safety and operational benefits of traffic-control devices based upon average or normal conditions.