Lane Departure Warning Assistant (LDWA) systems warn the driver when he/she leaves the lane unintentionally. To determine the potential effects of LDWA on road safety and road capacity in the Netherlands, a field operational trial (FOT) was initiated. The research shows that LDWA systems will have a slight positive impact on road safety. A positive effect of road safety also means a marginal impact on incidental congestion (because of the reduction in accidents). The maximum effect on traffic safety is a reduction of 9% of the casualties sustained in accidents involving heavy goods vehicles or buses on 80, 100 and 120 km/h roads in rural areas. There is no direct effect of LDWA on structural congestion or on road capacity. However, a reduction in accidents implies a maximum reduction of 11% of delay and traffic queues resulting from incidental congestion. If LDWA systems are used in situations where an extra lane is added by using the emergency land and/or narrowing existing lanes, there may be a slight positive effect on road capacity. The effect of LDWA on traffic safety and traffic flow is probably somewhat optimistic due to the following: 100% penetration in the Heavy Goods Vehicles (HGV) sector is unlikely; drivers cannot prevent all side-swipe and run-off road accidents, even if the LDWA system warns of an impending lane departure. For example, in a situation with no shoulder available; it is to be expected that a part of the positive effect of LDWA will disappear in time. (Author/publisher)
Abstract