Most motor vehicles have internal combustion engines. They are fairly cheap, easy to maintain, reliable, safe and small. Since IC engines burn fuel, they have long ranges but pollute the environment. A related engine is the external combustion engine. An example of this are steam engines. Aside from fuel, steam engines also need water, making them impractical for some purposes. Steam engines also need time to warm up, whereas IC engines can usually run right after being started, although this is not recommended in cold conditions. Steam engines burning coal release sulfur into the air causing harmful acid rain.

There are over 1 billion bicycles in use worldwide.^[22] According to 2002 estimates, there are around 590 million cars in service in the world and 205 million motorcycles.^[23][24] The most popular vehicle model in history is the Chinese Flying Pigeon bicycle, with on the order of 500 million in service.^[25] The most popular motor vehicle is the Honda Super Cub motorcycle, having passed 60 million units in 2008.^[26][27] The top selling car in history is the Toyota Corolla, with at least 35 million produced.^[28][29]