Interactions between buses and cars in a two-lane mixed traffic system

Abstract

This paper investigates the interactions between buses and cars traveling along a two-lane bus corridor. The dynamic behavior of these two kinds of vehicles is mimicked using a cellular automata model. A phase diagram of the operation of buses is obtained, and four phases are identified: (I) homogeneous and sufficient capability, (II) homogeneous and insufficient capability, (III) bunching and sufficient capability, and (IV) bunching and insufficient capability. In addition, the flow characteristics of cars are explored and the phase transition from a free-flow region to a saturated-flow region is observed. The latter relies not only on the probability of cars entering the corridor, but also on bus operation conditions due to the bottleneck effect. Interestingly, we find that the stability of bus fleets does not always deteriorate as a result of a higher probability of cars entering the corridor. In the case of high travel demand and frequent bus service, there is actually less variation in bus headway.