Automobiles are four-wheeled vehicles that are designed primarily for passenger transportation and are commonly propelled by an internal combustion engine using a volatile fuel. Most modern automobiles are complex technical systems with numerous subsystems that require special design considerations. Often, those considerations are driven by the need to meet specific vehicle performance requirements such as ride comfort, passenger capacity, high-speed handling, and power efficiency. Other factors may be economic, such as cost, durability, and emissions control.

The earliest automobiles were steam engines attached to wagons in the late 18th century, but they were slow and hard to handle. Karl Benz of Germany is widely credited with developing the first true automobile in 1885 or 1886. It is not clear exactly when he began working on the design, but the vehicle he built in 1888 or 1889 had a number of significant innovations, including a four-stroke internal combustion engine and a chassis to support the various automobile systems.

Today, the automobile is an essential part of life in most industrialized countries. It provides speed, convenience, and independence for individual owners, but it also encourages sprawl (i.e., straggling low-density urban development that degrades landscapes and causes traffic congestion). Automobiles are so important that entire societies have been restructured around their use.

The most popular type of automobile is a sedan, a car with two doors that can seat four people. Other types include hatchbacks, station wagons, SUVs (sport utility vehicles), vans, and pickup trucks. SUVs and minivans are often marketed as family cars because they can carry many passengers or large amounts of cargo. Trucks are designed for hauling heavy loads, and they can be used as work vehicles or for recreation.

Automobile designers are constantly challenged to improve the performance and safety of their products while reducing costs. Research and development engineers apply new technologies such as computer controls, advanced materials such as high-strength plastics and alloys of steel and nonferrous metals, and specialized components like air-conditioning. Moreover, the systemic nature of the automobile requires that the entire vehicle be designed as a whole, a requirement that has resulted in such innovations as independent suspension for all wheels, electric self-starters, and four-wheel brakes.

The 2021 Mazda CX-50 is the newest addition to our list, and it’s easy to see why. This compact SUV blends Mazda’s signature understated styling with a touch of ruggedness, and it offers a smooth driving experience. It also offers a number of standard infotainment features that are sure to keep families entertained on the road. And with a standard hybrid powertrain that gets up to 36 mpg in the city and highway, it’s one of the most efficient vehicles on the market.