Rural A roads in the UK (speed limit typically 100 km/h) have a higher accident involvement rate than motorways and the highest accident involvement rate for fatal accidents compared to all other road types. A high proportion of these accidents occur on curves. This study developed and tested four speed-reducing methods (Variable Message Sign, in-car advice, speed limiter and transverse bars) against a baseline condition. Driver performance, workload and acceptability were evaluated. As would be expected, speed limiters were the most effective measure; however, in terms of user acceptability this system was least preferred. All the other measures significantly reduced speeds when activated (although not as effectively as the speed limiter), in the order of approximately 6 km/h. It appears that the provision of information or support, in any format, could be effective in reducing speed on curves.(A)
Abstract