Developing a Speed Change Model of Vehicles in Highway Curve Sections

For road safety, an approach based on design speed has been used in the process of geometric design. However, drivers always do not drive below the design speed, and select their speed based on geographical features, roadside condition, road alignment, weather condition, etc. In this paper, hypotheses of previous studies were verified that design speed based approach did not reflect driver's actual speed, and therefore a complementary measure was presented. Speed data in rural 2-lane highways were collected, and an estimation model of maximum speed change during driving in curve section was developed. The relationship between accident data in rural 2-lane highways and maximum speed change was analyzed. These analyzed models and results can be utilized for judging the safety of highway curve sections.