Crash Prediction Models on Truck-Related Crashes on Two-lane Rural Highways with Vertical Curves

Reduced model I -for crest curves only and 3. Reduced model II -for sag curves only.The dataset includes 1,935 vertical curve segments with 205 truck crashes from 2002-2006.In second and third objective, Full Bayes approach is used to enhance the results obtained in the Reduced Models I and II.These results are then compared to the initial models.The fourth objective is evaluating the vertical curve variables which are statistically significant with truck-related crashes.These results show that higher grade change for the length of the vertical curve, total width in the range of 24 to 26ft, more number of passenger cars and trucks, increases the truck-related crashes on both crest and sag curves.Low speed limit on crest curves and high speed limit on sag curves increases truck-related crashes which may seem counter intuitive.The fifth objective is to provide suggestions on effective methods to reduce truck related crashes and improve safety.Some potential areas for design improvement may include flattening of steep vertical curves, advisory speed signs and increasing the roadway width on rural vertical curves in Ohio.