Vehicle relocation and staff rebalancing in one-way carsharing systems

• This study addresses joint optimization of vehicle relocation and staff rebalancing.
• Two integrated travelling salesman formulations are used to model the problem.
• Fleet size is more sensitive to demand than staff size.
• Staff size is inversely related to marginal vehicle cost.
• Total vehicle relocation time increases with marginal vehicle cost.

A solution to the imbalance of vehicles in one-way carsharing systems is vehicle relocation which involves staff members to redistribute the vehicles between stations. Vehicle relocation, however, can lead to an imbalance of staff members between stations. Thus, staff members, themselves, need to be relocated between stations to perform the vehicle relocations. This study addresses the joint optimization of vehicle relocation and staff rebalancing using two integrated multi-traveling salesman formulations. Results show that fleet size is more sensitive to demand than staff size, staff size is inversely related to vehicle cost, and that vehicle relocation time increases with vehicle cost.