Measurement and comparison of acceleration and deceleration zones at traffic control intersections

Acceleration and deceleration characteristics are basic driving behaviors that influence signal control and road geometry. Most previous studies focused on acceleration and deceleration rates under ideal conditions, i.e., on characteristics of lead vehicles, which might not adequately reflect the full spectrum of traffic operations. This paper presents a methodology for determining acceleration and deceleration rates and zone lengths for vehicles approaching and leaving intersections under likely uncongested traffic conditions, regardless of queue position. These characteristics are derived from speed profiles gained from vehicles equipped with Global Positioning System (GPS) instrumentation. With the speed profiles obtained from GPS-equipped vehicles, a series of data-processing algorithms is developed to measure the acceleration and deceleration behavior of vehicles approaching and departing an intersection. Acceleration and deceleration rates and zone lengths are estimated for several road categories. These zone lengths are compared with recommended values from AASHTO's A Policy on Geometric Design of Highways and Streets (Green Book), in which it is seen that the zone lengths under light traffic conditions are longer than the Green Book's values. In addition, determined acceleration and deceleration rates and zone lengths are found to depend on the underlying assumptions and calculation methods of the analysis.