Stops at traffic signals

The queue length, delay and stop rate at isolated undersaturated traffic signals are discussed. Each of these three performance measures is considered to consist of a uniform and a random component. The component which allows for randomness is related to the average overflow queue which is calculated explicitly by the miller method. An equivalent overflow queue formula is given based on webster's method for calculating the average queue length at the start of the green period. A formula is given for predicting stop rates at isolated undersaturated signals, which is considered to be satisfactory for most practical purposes. The formula may predict stop rates higher than one for flows approaching capacity because of multiple stops in oversaturated cycles. The formula also allows for a reduction due to partial stops, ie, vehicles which slow down without coming to a complete stop. Formulae for pedestrian stops, delays and queues are given. The discussions include the consideration of fuel consumption calculations and coordinated signal cases. It is suggested that simulation and other methods, and existing control practices, which ignore multiple stops are severely restricted in their prediction of, or effectiveness in reducing, vehicle fuel consumption and pollutant emissions at traffic signals. A numerical example and a method for the calculation of a stop reduction factor to allow for partial stops are given in the appendices.

Language

  • English

Media Info

  • Pagination: 182-92
  • Monograph Title: Procedures for analysis of traffic flow patterns using detector loops
  • Serial:
    • Volume: 10
    • Issue Number: 4

Subject/Index Terms

Filing Info

  • Accession Number: 01439198
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ATRI
  • Created Date: Aug 24 2012 10:04PM