Angelastro, Michael. The influence of driver sight distance on crash rates and driver speed at modern roundabouts In the United States. Retrieved from https://doi.org/doi:10.7282/T3251H8M
DescriptionThe majority of the existing speed and crash models in use today were developed based upon data from modern roundabouts located outside the United States. These models utilized geometric and operational characterizes as independent variables to predict passenger vehicle speed and crashes at modern roundabouts. This research intended to provide critical insights into the relationship between available diver sight distance and driver speeds and crash rates. This research will provide a tool for researchers, traffic engineers and highway designers to evaluate existing roundabouts to improve safety at these facilities. This research investigated the driver sight distance as an independent variable to predict passenger vehicle speeds and vehicle crash rates at roundabouts in the United States based on data collected at twenty-six (26) single-lane roundabouts. Three (3) regression models indicate driver sight distance is a statistically significant predictor of 85th percentile approach speeds, 85th percentile entrance speed and the difference between the 85th percentile approach speed & the 85th percentile entrance speeds at the entrance to a roundabout. The speed models are found to explain between 61% and 91% of the variability in the 85th percentile approach speeds, 85th percentile entrance speed and the difference between the 85th percentile approach speed & the 85th percentile entrance speeds. The five (5) crash rate models developed in conjunction with this research have R2 values from 0.26 to 0.40. The models developed in conjunction with this research produced statistically significant crash models utilizing driver sight distance as an independent variable. This research showed that vehicle speeds and crash rates at modern roundabouts in the United States are related to driver sight distance.