The chassis is definitely a Freightliner. That's Daimler's American truck subsidiary. The ambulance box could be made by any of several makers.
BTW - Freightliner sells the Mercedes-Benz Sprinter here, with Freightliner and Dodge badges. Sprinters are popular delivery trucks here (Fed Ex, etc.) but they're not used much for emergency vehicles as they are in the rest of the world. The heavier chassis (as above) is probably the most popular brand here for modular ambulances.
BTW - Freightliner sells the Mercedes-Benz Sprinter here, with Freightliner and Dodge badges. Sprinters are popular delivery trucks here (Fed Ex, etc.) but they're not used much for emergency vehicles as they are in the rest of the world. The heavier chassis (as above) is probably the most popular brand here for modular ambulances.
Added by Mike Feldman on 17 June 2010.