Measuring and modeling of delay components at signalized intersections

• Published in: Journal of engineering and applied science (Online) 2002-04, Vol.49 (2), p.225-240
• Main Author: Mousa, R M
• Format: Article
• Language: English
• ISSN: 1110-1903

The vehicular delay is an essential tool for measuring the performance of signalized intersections. This paper presents a methodology for measuring and analyzing stopped delay as well as acceleration and deceleration delay at a traffic signal. Field data were collected at 12 screen lines defining a 'system' where randomly selected vehicles are traced for about 355 m. Results indicated that deceleration and acceleration lengths of vehicles stopped at the intersection varied over a wide range and so did the deceleration and acceleration rates. The average deceleration - acceleration delay was estimated at 11.8 sec/veh. The delay due to non-stopped vehicles comprises only about 7% of the total delay, which can be neglected and intersection delay can be estimated from delay of stopped vehicles at a 93% confidence level. Relationships between delay components were modeled and the analysis showed a ratio of the total delay to stopped delay equal to 2.0, which is significantly higher than the 1.3 - factor adopted in the 1994 American HCM. The approach delay comprised about 85% of the total delay, indicating significant percentage of total delay to take place downstream of the intersection stop line.