An army convoy left the White House on 7 July 1919 and finally arrived in San Francisco two months later:
The Army’s road trip got off to a rocky start, with several vehicles breaking down that afternoon on the hilly roads leading out of the District. The party made camp the first night in Frederick, Md., where a brevet lieutenant colonel joined the group as a last-minute observer for the Tank Corps. Dwight D. Eisenhower, then 28, was there “partly for a lark and partly to learn,” he wrote later, because “nothing of the sort had ever been attempted.”
In the weeks ahead, engine troubles plagued the convoy, which progressed at an average pace of less than 6 mph. Still, the expedition continued to attract national attention, and large crowds regularly turned out in town squares as the convoy worked its way west. In Pennsylvania, newspapers reported that the vehicles were greeted by “a large delegation of State and city officials to accompany the convoy into Gettysburg.” State police escorted the convoy across Ohio, and politicians in Iowa opened their dining rooms to the traveling soldiers.
On Sept. 6, 1919, the vehicles limped into San Francisco, where the daily log appreciatively noted “fair and warm” weather and fine “paved city streets.”
Eisenhower, we all know, later signed the Interstate Highway Act. Today a motivated driver can get from Washington to San Francisco in a little more than three days.