I photographed this 1918 Model TT Ambulance at the National Museum of the USAF. The Model TT was the truck version of the Model T, produced with a beefier frame and rear axle.
Of course this is very similar to the Ford 1917 Model T Ambulance on display at the National Museum of Military Vehicles in Dubois WY; but also the Dodge WWI Ambulance seen at NAS Pensacola.