01628138

Component

Capacity Manuals use vehicle delay to assess the level of service for signalized intersections. Average delay is typically derived from capacity and traffic volume during an analysis period using adapted approaches on the basis of queueing theory. Variability of traffic volume during the analysis period can influence the resulting delay and needs to be taken into account. The impact of non-stationary arrival flow rates is not yet explained completely by queueing theory, therefore a simulation study is performed. The analysis of measurement data shows that traffic volume during the peak hour can be distributed in very different forms. A set of abstract flow patterns is derived, representing simplified flow profiles of the peak hour, split into 15-min-intervals. Microscopic traffic flow simulations are performed for different signal control programs and volume-to-capacity ratios to determine the delay caused by the different flow patterns. It is shown that in most cases delay is higher for non-stationary flow than for stationary flow. Finally, a correction factor is developed for the delay computation method used in the German Highway Capacity Manual (HBS) to better reflect the volume distribution within the design hour.

This paper was sponsored by TRB committee AHB40 Standing Committee on Highway Capacity and Quality of Service.

01618707

17-02552

English

15p

2017

Transportation Research Board 96th Annual Meeting

Digital/other

Figures; References

Highway capacity; Level of service; Signalized intersections; Simulation; Traffic delays; Traffic flow; Traffic volume

German Highway Capacity Manual

Non-stationary traffic conditions

Highways; Operations and Traffic Management; Planning and Forecasting

Transportation Research Board Annual Meeting 2017 Paper #17-02552

TRIS, TRB, ATRI

Dec 8 2016 10:58AM