Double-decker bus
With the exception of coaches, double-decker buses are uncommon in the United States. Many private operators, such as Megabus, run by Coach USA, employs double-decker buses on its busier intercity routes.
Doble steam car
Doble made two further steam engines, designated models G and H. These were larger units and used experimentally in several buses. The first were tested in 1926 by International Harvester, using a Doble Model G engine, and the Detroit Motorbus Co, in a double decker, with a Doble Model H engine. A second Detroit bus had a Doble steam engine added in 1927 and at least one of them covered some 32,000 miles. In 1929 a Doble Model H was installed in a Yellow Coach for General Motors. This was followed by another Model F in a Fageol bus.