Effects of passing lanes on highway traffic flow

In this paper, the effects of passing lanes on traffic flow on a single-lane highway are investigated based on a cellular-automaton (CA) model proposed by Lee et al. (2004) with periodic boundary conditions. A new driving strategy for the diverging and interacting processes are proposed by considering dual-time-headways (an interaction headway and a safe headway) as the criteria for a vehicle to select a lane or change lane. The proposed dual-headway rule has a clear physical sense and can be calibrated in the real world. We can see that (i) At low- (or high-) densities, there are no obvious increases of flux due to very weak (or very strong) interactions between vehicles. However, flux has an obvious increase at intermediate-density regions with the increase of the length of a passing lane; (ii) the space-time patterns before a passing lane are different from that after a passing lane, which is caused from vehicular reconfigurations on a passing zone; (iii) passing lanes can merge several narrow jams into one or few wide jams when increasing the length of passing lanes; (iv) if vehicles are allowed to travel with even higher speed, traffic can be further improved.