Effects of the intelligent road lighting on traffic flow and night-time pedestrian recognation on a rural road

In January 1999 Fortum, IVO Transmission Engineering Ltd (IVO) launched a project aiming for an intelligent pilot road section, where road lighting and variable speed limits are controlled optimally. For the calibration of the controller, more information on the effects of luminance on traffic flow was needed. Hence, two studies presented in this paper were conducted. First, the effects of four illumination steps (469W, 257W, 172W, no lighting) on traffic flow were studied. The second study was designed to investigate the effects of three road lighting steps on recognition of pedestrians. The traffic flow analyses showed that the increased lighting power did not increased the mean speed, neither proportion of short headways on the test site. On the contrary, the luminance had significant effect on driving behaviour. The high luminance decreased the mean speed as well as proportion of short headways. The main results of the study 2 showed that lighting affects the recognition distances of night-time pedestrians. Each lighting step met a frequently mentioned criterion distance of 100 m. This distance should be required considering the normal night-time driving speeds on the roads. Conclusively, the studies gave new information on the relationship between illumination and driving behaviour for the development of the control model of the intelligent road lighting management system. However, there is place for further studies to cover more weather and road conditions.