A short-turning strategy to alleviate bus bunching

Some stops on busy bus lines regularly suffer from bus bunching, which refers to a bus arriving with a little headway to its predecessor. This phenomenon increases scheduling difficulties and has a negative impact on the passenger experience due to unreasonable scheduling. The conventional holding strategy aims to alleviate this problem by holding buses at control points. However, the holding strategy has the drawbacks of creating large deviations from the original schedule and prolonging passenger waiting time when confronted with traffic congestion. This study proposes an innovative short-turning strategy to alleviate bus bunching by the deliberate conversion of a few regular trips to short-turning trips. A nonlinear optimisation model is developed by rescheduling a set of trips using the short-turning strategy to minimise schedule deviation from the original schedule. The nonlinear short-turning model is then converted into a linear form that is solvable by CPLEX. Based on real data from the Yuntong 111 bus line in Beijing, China, the proposed short-turning strategy is deployed in a simulation experiment. The results show that the short-turning strategy is superior at alleviating bus bunching than the alternatives of no control strategy and the holding strategy. Compared with no control strategy, the short-turning strategy can achieve a more than 43.44% reduction in schedule deviation and significantly reduce total passenger waiting time by up to 8.99%.