Cost-benefit analysis of extra brake lights

The aim of the investigation is to clarify the economies of introducing window-mounted extra brake lights on passenger cars. The parameters used were price of lights (one or two), reduction in the number of accidents, private and socio-economic accident costs, discount rate, and how the regulation should be implemented, a) all passenger cars at one time or b) new-registered passanger cars. We have considered the expected development of the vehicle stock and rear-end collisions during a 20-year payback period and the real costs of rear-end collisions. Extra brake lights are a profitable measure if they reduce the costs of rear-end collisions by 15, 11, 7 and 13 % in Denmark, Finland, Norway and Sweden respectively. If we assume an accident cost reduction of 20 % for rear-end collosions and a discount rate of 6 %, the investment is repaid in 12, 8, 5 and 10 years respectively in the countries referred to. The most economically-sound of the above measures is alternative b). One light is more economical than two lights. According to the majority of the roughly 60 Nordic experts interviewed in the investigation, the accident-reducing effect of extra brake lights is higher than that required to make them economically justified. If we consider the socio-economic estimates, the profitibality of the measure increases by almost a third.