A New Level of Service Method for Roads Based on Available Perception Time and Risk of Sustaining Severe Injury or Death

The purpose of this paper is to present three novel methods of road traffic flow level of service on the basis of safety, prevention of accidents by available perception time and available stopping distance, and the risk of pedestrians sustaining severe injuries and risk of death. The risk of accidents and risk of sustaining severe injuries or death increase with the reduction of gap between the vehicle and the pedestrian casualty. Hence, the closest the pedestrian is from the vehicle the more likely he/she will sustain sever injuries or die. Researchers have assessed the impact of an accident by passenger cars and light goods vehicles on pedestrian, but they overlooked the impact of heavy goods vehicles. For roads with relatively high percentage of heavy goods vehicles in the traffic flow, an investigation of the risk of losing human lives and high expenses due to accidents is beneficial. Level of service methods that describe the risk of accidents in low quality operational conditions are necessary for accident prevention purposes.