W.A. Stevens was established in Maidstone, Kent in 1897 and had by 1906 built its first petrol-electric vehicle. According to the website of the Birmingham Motor Museum the simpler to operate petrol-electric transmission was popular among bus drivers rather than the conventional crash gearbox (in the days before synchromesh) as few bus staff had previously driven motor vehicles. As it was so popular the company was purchased by a large bus operator, Thomas Tilling, and renamed Tilling Stevens.
A petrol engine was connected to an electricity generator; the current produced passed to a motor which drove the rear wheels. Tilling-Stevens consolidated its position with bus operators in the World War I because the petrol electric chassis were not considered suitable by the Army for use in France. However many men were trained to drive in the War on vehicles with conventional gearboxes which led to a decline in popularity of Tilling-Stevens’ system.
Tilling-Stevens also produced a goods chassis available with either petrol-electric or conventional petrol engines and built many trucks during the War. After the war, they failed to invest in updating their products and acquired Vulcan Trucks of Southport, Lancashire in 1930 to extend their range (and use Vulcan petrol engines). Production stayed at Maidstone and during the World War II they specialised in searchlight trucks.
In 1950 the company was sold to Rootes Group, and complete vehicle production ceased soon afterwards. The plant continued to produce light commercial engines and vehicle bodies, before finally closing in the 1970s, some years after the group had been acquired by Chrysler.
The Tilling-Stevens petrol-electric bus is interesting as an early example of a hybrid vehicle, although without any battery storage. As the petrol engine ran continuously, it was almost certainly less fuel efficient than a competing petrol engine, which may have contributed to its design. However hybrid petrol-electric cars, such as the Toyota Prius, are now seen as being a partial solution towards cutting CO2 emissions and reducing the risks of damaging global warming.