A study on correlation between skid distance and pre-braking speed

'Smart Highway' project is to pursue intelligent superhighway of no-congestion/no-accident in which up-to-date road technology, IT technology, and next generation automobile technology are mutually fused and compounded, and it requires more close communication between road and driver. Especially, sufficient understanding for automobile as the media between road and driver is required before constructing the intelligent road. Driver ordinarily takes sudden braking when urgent situation is developed at the front or when he is involved in an unexpected accident, and he may be inflicted upon accident in accordance with the stopping distance. As for factors exerting influence to the stopping distance of vehicle, recognition response time of driver, performance of vehicle's braking device, and state of road surface etc. can be mentioned, however, pre-braking speed can be referred to as the most important factor. Currently, in the investigating section of traffic accident, the state of overspeed is concluded by calculating pre-skidding speed based on the length of skid mark. However, in order to identify accurate cause of accident, estimation of pre-braking speed which takes into account speed reduction during transient time should be considered as a requirement. Therefore, from this study, we would like to propose the method to calculate exact speed information of vehicle at the time of traffic accident, and it is expected that this study can be a help for understanding the characteristic of vehicle when constructing intelligent road in the future.