Glossaries

Definitions: P - R

Pace Speed  –  The highest speed within a  range of speeds (typically within 10 mph) that represents more vehicles than in any other like range of speed (FHWA MUTCD, 2003)

Parametrics – A modeling platform with application areas that include urban, highway, public transport, congested, free flow, ITS and HOV. Additional information about Parametrics is available online at:  http://www.parametrics.com

Parking Lane  – See Lanes: Parking Lane

Passenger Car – A passenger automobile with similar size and operating characteristics of a car, sport/utility vehicle, minivan, or  pick-up truck.

Passing Lane  – See Lanes: Passing Lane.

Passing Sight Distance – See Sight Distances: Passing Sight Distance.

Pavement Markings – Devices or paint placed on the roadway to mark pavement for vehicular and pedestrian traffic control.

Pedestrian – Georgia State law defines a Pedestrian as: “Any person who is afoot” (GLC 40-1-1).  By state definition, roller skaters, in-line skaters, skateboarders, and wheelchair users are also considered pedestrians.

Pedestrian Refuge – Also referred to as a refuge island/area or pedestrian island, is a section of pavement or sidewalk where pedestrians can stop before finishing crossing a road (www.wikipedia.org).

Permit – A legal document issued by the Department authorizing an applicant to do specific work on state rights-of-way (GDOT Driveway Manual, 2004).

Posted Speed – The speed limit posted on a section of roadway.

Preventative Maintenance (PM) Projects – the planned strategy of cost effective treatments to an existing roadway system and its appurtenances that preserves the system, retards future deterioration, and maintains or improves the functional condition of the system without increasing structural capacity.

Profile – A longitudinal section of a roadway, drainage course, etc.

Profile Grade Line – The point for control of the vertical alignment. Also, normally the point of rotation for superelevated sections (NJDOT, 2006).

Project – "A portion of a highway that a State proposes to construct, reconstruct, or improve as described in the Preliminary Design Report or applicable Environmental Document (FHWA VE Website, 2005)."

Queue – When one or more vehicles is traveling less than 7 mph.  (SimTraffic, 2006) A vehicle is considered queued when it is either stopped at a traffic light or stop sign  or behind another queued vehicle .

Ramp Metering – Use of a traffic control device for the intent of regulating the flow of traffic entering a freeway.  The device, which is typically a traffic signal or a two-phase (red and green, no yellow) light, prevents multiple vehicles entering a freeway ramp.

Reaction Time – “The time from the onset of a stimulus to the beginning of a driver's (or pedestrian's) response to the stimulus, by a simple movement of a limb or other body part (FHWA, 2001 http://www.tfhrc.gov/safety/pubs/97135/glossary.htm#r)."

Retaining Wall – A structure that prevents dirt from sliding or eroding. 

Reverse Crown – See Crown: Reverse Crown

Reverse Curve – See Curves: Reverse Curve

Right-of-way (ROW or R/W) - All land under the jurisdiction of, and whose use is controlled by the Department (GDOT Driveway Manual, 2004).

Right-of-Way Flares – areas needed for sight distance triangles at an intersection that should be kept free of obstructions in order to provide adequate sight distance.

Roadside – The area adjoining the outer edge of the roadway (normally applies to freeways) (NJDOT, 2006).

   

Roadway - The portion of a highway, including shoulders, for vehicle use (NJDOT, 2006)

Roadway Characteristics – The geometric characteristics of the freeway segment under study, including the number and width of lanes, right-shoulder lateral clearance, interchange spacing, vertical alignment, and lane configurations.

Running Speed – For all traffic, or a component thereof, the summation of distances traveled divided by the summation of running time.

Rural Area – “Those areas outside the boundaries of urban areas (AASHTO Green Book, 2004)."

Rural Arterial - Functional classification for a street or hightway that integrates interstate and intercounty service, provides for movements between urban areas, and provides for relatively high travel speeds with minimum interference to through movement (AASHTO Green Book, 2004). 

Rural Collector - A street or highway that “generally serves travel of primarily intracounty rather than statewide importance and constitute those routes on which (regardless of traffic volume) predominant travel distances are shorter than on arterial routes. Consequently, more moderate speeds may be typical, on the average (AASHTO Green Book, 2004).”

Rural Section – Any roadway without curb and gutter. 

Rural Shoulder – The part of the roadway beyond the edge of travel that is graded or paved flush with the edge of travel to allow for emergency usage.