Street Design Manual

Traffic Engineering - The application of scientific and mathematical principles to facilitate the safe and efficient movement of people, goods and information. Traffic Impact - A measurable, quantifiable or qualified effect on one or more traffic performance measures. Traffic impacts can be beneficial or detrimental. Traffic Performance Measures - Synonymous with Measures of Effectiveness. Traffic Sign - A device mounted on a fixed or movable support, conveying a message or symbol to regulate, warn or guide traffic. Traffic Study - A collective term for Trip Generation Reports, Traffic Assessment Report or Traffic Impact Analysis Reports (see below) - a) Trip Generation Report: Calculates the expected number of new trips that a development will generate during the AM and PM peak periods. Trip generation reports are required for all rezoning cases. Exceptions can be made for rezoning cases that do not affect the trip generation characteristics of the property such as tree conservation areas, stormwater retention, location and size of building signs, etc. b) Traffic Assessment (TA) Report: Calculates the expected number of new trips and calculates the current amount of delay, queuing and traffic capacity available at the nearest intersection(s). If existing delays and volume-to capacity ratios are low, City staff may conclude that the adjacent roadway network can absorb new trips without becoming congested. In that case, no further study is needed. c) Traffic Impact Analysis (TIA) Report: Calculates the expected number of new trips and calculates the current amount of delay, queuing and traffic capacity available at the nearest intersections. TIAs calculate the amount of delay, queuing and volume-to-capacity ratio and other variables both before and after a development is built. City staff will then use engineering judgment to determine if the developers should mitigate some of the traffic impacts from their development by adding a new turn lane or installing some other improvement. If mitigation is recommended, the TIA shall recalculate the traffic impacts after the mitigation measures have been installed. It will quantify those impacts that can be directly attributed to the new development and the effect of any mitigation. Travelway - The travelway refers to the paved width of a street between curbs accommodates moving and stationary vehicles in a variety of modes. Trip - Travel between an origin and a destination. Traffic Volume - The number of vehicles passing a given point during a specified period of time

Raleigh Street Design Manual – Page 109