Effect of novice driver's car-following characteristic on roadway segment capacity

Abstract

The presence of significant proportion of novice drivers greatly affects traffic flow performance due to their poor driving skills. The primary objective of this study was to develop adjustment factors to evaluate the impacts of novice driver's car-following characteristic on roadway segment capacity. On-road experiments were conducted for measuring the car-following behavioral data associated with novice and experienced drivers. Comparative analyses were conducted. It was found that novice drivers preferred keeping significantly larger spacing and headways than experienced drivers did. Linear regression analyses were conducted to relate travel speeds to spacing and headways. Adjustment factors were developed to quantitatively evaluate the effects of novice drivers' car-following behaviors on roadway segment capacity. It was found that as the proportion of novice drivers in the traffic stream increased, the reduction rate of capacity had the same trend of increasing. The presence of novice drivers may result in up to 13% of capacity reduction when traffic flow composed entirely of novice drivers traveling with an average speed of 90 km/h. The validity of implementing the novice driver adjustment factor was tested against measured data. The results of validation determined that the proposed adjustment factors improve the estimation accuracy of roadway segment capacity.