Safety at Rail-Road Level Crossings

Doctoral thesis, 1993

Safety related to traffic at rail/road level crossings has long been a major issue for rail operators all over the world. Eliminating these level crossings entirely would be a desirable solution. However converting them into separate types is very expensive and not reasonable in many cases, e.g. where the traffic intensity is low. For this reason a research program should be started aimed to meet the following main requirements: 1. The safety awareness of the driver as the main decision-making unit should be increased. This may help him/her accept a lower risk when intending to pass over a level crossing. 2. Crossings should be designed to provide more convenient information to the driver. 3. Tail vehicles should be deisgned to protect the passengers in a critical collision situation. This thesis summarises some research studies concerning the above-mentioned requirements. In papers I and II, road driver behaviour at passive crossings is focused. A decision model for a simulation program was developed. The purpose of the study reported in papers III and IV was to find out whether risk analysis methods either forwards or backwards, could successfully explain the mechanism responsible for the occurrence of collisions at rail/road level crossings. The results show that application of these methods at a disaggregate level is feasible in order to explain single accidents. Paper V.1 and V.2 analyse a situation in which a light rail bus, travelling at 130-140 km/h, collides with a stationary heavy truck. The aim was to find out whether a combination of energy absorption capacity and some type of emergency brake system would offer increased protection to passengers in light rail vehicles. The results of the study indicate that under some realistic assumptions a survival impact speed as high as 70 km/h can be achieved, provided that the rail vehicle is fitted with a deformation zone of 1.5 m length, and an emergency retardation rate of up to 3.5 m/s.