Influence area of speed cameras: based on naturalistic driving data

Abstract

Speeding is a major problem worldwide contributing for a large number of crashes and injuries. In order to control the vehicle speeds, the traffic authorities have enforced speed regulations which are monitored by the speed cameras. However, these speed cameras tend to alter the driver behaviour affecting the vehicle kinematics. This thesis examines the influence area of such speed cameras on driver behaviour using naturalistic driving data. Several locations from the UK and Poland were selected for the analysis consisting of various camera types. Kinematic data of the vehicles passing through the selected locations were extracted and analysed for a pre-defined range of distance around the camera. The study indicates that the driver behaviour was influenced by the presence of speed cameras. Drivers were found to reduce the speed before the camera and immediately started to increase the speed after the camera resulting in a V-profile in the vehicle speed. For the UK, the average speed drop before the camera was found to be 0.87m/s (3.13km/h) and the average speed rise to be 0.89m/s (3.2km/h) after the camera. The decelerating and accelerating distance were observed to be 182m before the camera and 166m after the camera respectively contributing to the influence area of 428m around the camera. In case of Poland, the average speed drop before the camera and the average speed rise after the camera were found to be 1.01m/s (3.62km/h) and 1.01m/s (3.64km/h) respectively. The deceleration distance and acceleration distance were found to be 194m before the camera and 125m after the camera respectively summing up for an influence area of 319m around the camera. With the help of naturalistic driving data this study observes the behaviour from the driver’s point of view for a fixed speed camera and an average speed camera. The behaviour from the average speed camera shows less variation in the speed when compared to a fixed speed camera. However, the results should be taken with caution as the number of cases are limited. Analysis of a larger number of cameras would give a definite result which can be an aspect for the future study. It would also be interesting to compare results from naturalistic driving study with an on-field study using external speed recording devices.