With a bulldog named Bud and a $50 wager on the line, Dr. Horatio Nelson Jackson unwittingly created an American tradition. In May 1903, he set out to prove it was possible to drive an automobile across the country from sea to shining sea. Without a map, a windshield, or any gas stations along the route, he deliberately made his way from San Francisco to New York in 63 days, completing the first transcontinental road trip.
http://www.oregonlive.com/travel/index.ssf/2009/07/road_trips_and_national_parks.html