Coupling effect modeling of driver vehicle environment factors influencing speed selections in curves

It is of significant importance to select an appropriate speed for a vehicle to drive through an upcoming curve. Previous studies have mainly taken into account the vehicle–road interaction, which lacks quantitative analysis of drivers’ driving behavior related to curve speed selections. In this study, a curve speed model derived from the vehicle–road coupling effect analysis is combined with drivers’ driving styles which are classified into aggressive and moderate styles. Moreover, a driver behavior questionnaire based analysis is carried out for quantitative identification of the above two groups of drivers, compared with the traditional vehicle-motion-indexed classification of driving styles. Unlike previous curve speed models, the proposed model not only takes the vehicle–road coupling effect into consideration, but also introduces a driving style factor which is quantified with both driver behavior questionnaire analysis and vehicle-motion-indexed classification. The proposed curve speed model was validated with the road test data. It is found that the proposed curve speed model considering both the vehicle–road interaction and drivers’ driving styles could effectively guarantee traffic safety and riding comfort in sharp curves.