Characteristics of red light violators: Results of a field investigation

Motor vehicle crashes at traffic signals are a major source of injuries and property damage, especially in urban areas. Many crashes result from vehicles entering the intersection after the onset of a red light, a traffic violation that may be affected by the duration of the change interval (the yellow and all-red periods of the traffic signal). The purpose of this study was to examine short-term and sustained effects on red-light compliance and potential vehicle conflicts as a result of an increase in change intervals to values associated with the Institute of Traffic Engineers (ITE) proposed recommended practice for determining vehicle change intervals. Data were collected during an experiment in an urban location involving changes in signal timing at some 10 intersections. Observations included the proportion of signal cycles with vehicles entering on a red light and the proportion of vehicles exiting the intersection after the onset of a conflicting green signal. Results indicate that change intervals...

Influence of Traffic Signal Timing on Red-Light Running and Potential Vehicle Conflicts at Urban Intersections

Deceleration characteristics of vehicles are important for intersection design, deceleration lane design, traffic simulation modeling, vehicular emission and fuel consumption modeling, etc. Heterogeneous traffic stream consists of vehicles with wide variation in their physical dimensions, weight to power ratio and dynamic characteristics, which affect their deceleration behaviour. The majority of past studies are restricted to deceleration behaviour study of cars and trucks in homogeneous traffic. The present study aims to analyze the deceleration behaviour of different vehicle types (like truck, car, motorized two and three-wheeler) on Nagpur-Mumbai Express Highway at Wardha, India. Drivers were asked to decelerate their vehicles from their maximum speed to zero speed in the shortest time and their speed profiles were collected using Global Positioning System. Deceleration behaviour of different vehicle types is significantly different. Vehicles with higher maximum speed have higher deceleration time, deceleration distance, maximum and mean deceleration rates during their deceleration manoeuvre. In deceleration manoeuvres, vehicle’s deceleration rate initially increases, attains the maximum deceleration and decreases afterwards. A dual regime model is developed to describe deceleration behaviour over the entire speed range of all vehicle types except cars. For cars, a second order polynomial is proposed.

http://www.ijtte.com/uploads/2012-10-01/5ebd8343-9b9c-b1d4IJTTE%20vol2%20no3%20%287%29.pdf

Study of Deceleration Behaviour of Different Vehicle Types

The development of an automatic method of safety monitoring at Pelican crossings

This study analyzes field data gathered from 60 test subjects to characterize driver deceleration rates at the onset of a yellow-phase transition on high-speed signalized intersection approaches using an in-vehicle Global Positioning System. The driver rate of deceleration is analyzed for five yellow-phase trigger times to stop line (1.6, 2.7, 3.3, 4.4, and 5.6 s) as drivers approach the intersection at a speed of 72 km/h (45 mph). Results of the study, based on a sample of 821 deceleration events, indicate that driver deceleration rates range between 1.51 and 7.47 m/s2 (5-24.5 ft/s2) with a mean value of 3.27 m/s2 (10.7 ft/s2). Mean deceleration rates varying from 2.2 m/s2 (7.2 ft/s2) for the longest time to stop line (5.6 s) to 5.9 m/s2 (19.4 ft/s2) for the shortest time to stop line (1.6 s) demonstrate that drivers use more time to decelerate if they are sufficiently away from the intersection. Statistical analyses were used to investigate the effects of the time to stop line, gender, age group, and gr...

Evaluation of Driver Deceleration Behavior at Signalized Intersections

Driver and traffic characteristics associated with change intervals were studied at five intersections in the Tucson metropolitan area. The field studies were conducted to document the influence of (a) the variation in the duration of the yellow interval, (b) the effect of enforcement, and (c) intersection approach grades. Before and after studies were used at two of the intersections to evaluate the influence of extending the duration of the yellow interval. Generally, the major difference that resulted from a 4-sec yellow interval rather than 3 sec was the reduction in the percentage of the last vehicles through the intersection that entered on the red signal indication. The effect of enforcement was tested with a police vehicle located at the intersection approach. Although there was a reduction in the percentage of vehicles that entered the intersection on the red signal interval, other measures of driver and traffic characteristics generally showed no significant difference.

Traffic characteristics during signal change intervals (abridgment)

Vehicles stopping at signalized intersections were examined for the purpose of evaluating the validity of the common assumption of constant and uniform deceleration rates. The data set consisted of the first vehicles to stop upon the onset of the yellow signal interval with measurements of the initial approach speed, deceleration time, and deceleration distance. The deceleration rate may be computed using only two of the three measured values; thus the rate for each vehicle can be determined by three differnt equations. With nonuniform deceleration profiles, the equations will produce different values; and the degree of nonuniformity can be determined by comparing the differences in the computed deceleration rates. The analysis of the field observations indicated that 69% of the vehicles demonstrated deceleration profiles associated with nonuniform deceleration rates. Furthermore, the deceleration profile and the degree of nonuniformity were found to be a function of the initial approach speed.

An evaluation of vehicle deceleration profiles

Data from field studies of intersections in Arizona and information from the literature were used to make an in-depth examination of the traffic signal change interval. This examination included a review of the traditional concept and theory on which the determination of the change interval has been based and an evaluation of the applicability of this theory. The analysis of driver behavior and characteristics indicates that the majority of drivers do not conform to the model, which assumes a constant or uniform deceleration rate. In fact, the deceleration profile is related to the approach speed. An analysis of the first vehicle to stop at an intersection and the last vehicle to clear the intersection was made based on the time from the intersection at the onset of the yellow interval. This analysis revealed that the time for the last vehicle to clear the intersection is more critical in the design of the yellow interval. It is concluded that a uniform 4-sec yellow interval would be acceptable.

Thomas C Fox

Papers

Traffic characteristics during signal change intervals (abridgment)

An evaluation of vehicle deceleration profiles

A reassessment of the traffic signal change interval