This article proposes an optimal jam-absorption driving (JAD) strategy, which not only prevents the occurring traffic oscillation but also avoids the consequential jam caused by the JAD vehicle. We first conducted a theoretical analysis to estimate the relationship between velocity and space headway within kinematic waves. Then an optimization function was formed to minimize the system travel delay. A procedure for specifying the absorbing vehicle was proposed. The performance of the JAD strategy was validated in a simulation model developed for the connected and automated driving environment. The results showed that by reaching a balance between the space headways in the 'slow in' and 'fast out' JAD execution stages, our optimal JAD strategy can successfully eliminate the oscillation without causing consequential jams. The collision risks measured by surrogate safety measures were reduced by 14.63% to 44.22% during the oscillation. Our strategies outperformed some previous ones in the same traffic condition. The proposed JAD strategy can effectively improve the safety situation on the freeway by eliminating traffic oscillations.
- jam-absorption driving
- kinematic waves