Bus Design

Development

In 2012 some 193,000 buses were manufactured worldwide, with the top five countries (China, Brazil, South Korea, Russia, and Japan) producing 78 percent of them. In comparison, 21 million trucks were built worldwide. The importance of this is that bus production is not large enough in any country to support mass production as a single product vehicle. Bus costs are kept relatively low by using mass-produced parts from the truck industry, including engines, gearboxes, axles, suspension, and steering.

The motor bus development was accelerated by World War I, when lorries were used to carry supplies to war zones and buses carried soldiers. At the end of that war, many surplus buses and trucks were put into service for both urban and rural traffic. This first generation of buses was powered by gasoline engines and ran on solid-rubber tires. With the poor state of road surfaces, this gave a most uncomfortable ride compared to streetcars, that dominated urban transit at the time. Two developments improved ride quality: first, tarmac (smooth) surfacing of roads, and second, the adoption of pneumatic tires.

World War II brought diesel engine reliability to the same level as gasoline engines with better fuel economy; this led to the rapid replacement of gasoline engines with diesel engines for buses.

Technology

The technology used for buses piggybacks on the mass truck market. In the last 30 years there has been a rapid change in the way buses are designed and operated. Historically, the bus engine and steering wheels were at the very front of the bus, with the entrance at the back or in the middle. This required a two-man crew—a driver and a conductor who collected the fares. Due to limitations of tires, these buses were small, carrying about 40 passengers, and in a number of countries also included an open-top upper deck, allowing about 50 passengers. These first buses weighed only about four tons.

...