Emergency vehicles need to reach their destination as fast as possible. They deserve the highest priority at intersections. Therefore, they are allowed to use bus lanes and pass red lights at traffic light systems. Nevertheless, for emergency vehicles it is still quicker and safer to get priority at the approaching intersection. This paper analyses how the travel time of emergency vehicles can be improved by using vehicle-to-infrastructure (V2I) communication. Emergency vehicles are sending messages with their route information and their current position. The traffic lights which have to be passed can switch to green for emergency vehicles and to red for all other streets. The traffic lights continue the normal operation after the emergency vehicle has passed the intersection. Simulation results show that emergency vehicles can reach their destination faster.