Davidson - Cadillac armored car The Davidson - Cadillac armored car of 1915 was developed on a Cadillac chassis by Royal Page Davidson and the cadets of the Northwestern Military and Naval Academy in Highland Park , Illinois . This military vehicle is the " first true " fully armored vehicle made in the United States because it was built specifically just for that purpose and was not a conversion of an automobile or truck . Description . The Davidson car was armor clad around the entire vehicle . It had radiator doors that would open for access and the rear part had an open top , where a machine - gun was mounted just behind the driver . History . Royal P . Davidson in 1915 commanded a special fleet of eight military vehicles on a convoy from Chicago to San Francisco to evaluate their performance . The vehicles he designed for military use were built by Cadillac . The column included a reconnaissance scout vehicle with instruments for observation , two wireless radio communications vehicles , field cooking vehicle complete with fireless cookers , a hospital vehicle with operating tables and an X - ray machine , a balloon destroyer , a quartermaster ' s car and the first " fully " armored military vehicle . War Department personnel representing the government went with the convoy to give reports on the performance of the vehicles . Some of the vehicles had rapid fire machine - guns and searchlights . Five were eight - cylinder vehicles . The Davidson - Cadillac fully armored military vehicle was capable of 70 mph when the roads allowed . It was America ' s first military fully armored vehicle . The reconnaissance scout vehicle was equipped with military rifles , map tables , instruments for making maps on the spot , a dictating machine , instruments for observation for seeing behind walls , altitude indicators , and range and elevation finders . The radio wireless communication vehicles came with telescope masts mounted on the running board . They came with generators to generate the normal current of 110 volts . One of these radio vehicles came with a rapid fire Colt automatic machine gun . It also had a powerful electric searchlight with a helograph shutter . The vehicles with the field kitchen and hospital were mounted on an eight - cylinder chassis of a 145 inch wheelbase . Cooking was done using an electric cooker that did not produce any visible fire . The armored vehicle came with bullet - proof steel . It had loopholes for firing out with rifles . It also had a rapid fire Colt automatic machine gun . It came with winch equipment so it could be pulled out of mud . The balloon destroyer vehicle came with a machine gun making it the first American anti - aircraft vehicle . Davidson had these military vehicles built to convince the government that a mechanized army was the way to go . Davidson and some of his school cadets drove the fully armored vehicle along with seven other support vehicles for 34 days from the Northwestern Military and Naval Academy in the Chicago area to the Panama Pacific Exposition being held in San Francisco in 1915 . The first military convoy across the country received much publicity from many newspapers nationwide . The military vehicles were shipped back by train to the Academy in Highland Park when the exposition was over instead of being driven back , since Davidson achieved his goal of demonstrating to the United States Army and the government that a mechanized army was the technology of the future . Davidson ' s Automobile Corps convoy of the 8 specially designed military vehicles were driven by the cadets of the Northwestern Military Academy as an escort for the Liberty Bell to the Panama Pacific Exposition on the Lincoln Highway in 1915 . This was the last time the Liberty Bell traveled from its home for any exposition .