Abstract: An emergency response vehicle such as an ambulance is provided with a warning unit that provides a visual and audible warning signal. The warning unit is mounted in a recess or cutout in the hood which covers the engine compartment of the vehicle. This positioning of the warning unit avoids blockage of the air flow through the radiator required for cooling of the vehicle engine. Brackets or other suitable devices are used to mount the warning unit, preferably to a wall such as a radiator support, so that the warning unit remains stationary during opening and closing of the hood. The wall also serves to block rearward passage of the noise generated by the warning unit.