Resource management in mobile hotspots is an interesting and challenging issue. In this paper, we propose a dynamic bandwidth allocation (DBA) scheme consisted of call admission control and bandwidth adjustment functions to lower handoff vehicle dropping probability and efficiently utilize a resource of a base station. Specifically, a handoff priority scheme with guard bandwidth is employed to protect handoff vehicles. On the other hand, a bandwidth is dynamically assigned to each vehicle exploiting vehicular user movement patterns which are getting on and off patterns at a stop. Simulation results demonstrate that the DBA scheme can guarantee low new vehicle blocking probability and handoff vehicle dropping probability.