Computer traffic simulation is important for making new traffic-control strategies. Microscopic traffic simulators can model traffic flow in a realistic manner and are ideal for agent-based vehicle control. In this paper we describe a model of a reactive agent that is used to control a simulated vehicle. The agent is capable of tactical-level driving and has different driving styles. To ensure fast reaction times and the agent's driving task is divided in several competing and reactive behaviour rules. The agent is implemented and tested in a prototype traffic simulator. The simulator consists of an urban environment with multi-lane roads and intersections and traffic lights and and vehicles. Every vehicle is controlled by a separate driving agent and all agents have individual behaviour settings. Preliminary experiments have shown that the agents exhibit human-like behaviour ranging from slow and careful to fast and aggressive driving behaviour.