The internal combustion engine reshaped nearly every dimension of modern life. It redefined how people work, where they live, what they eat, and how goods reach their doors. Together with electrification, it drove roughly 30 percent of U.S. productivity growth between 1899 and 1941, and economists consider that figure an underestimate because the data only captured a narrow slice of industries. Its influence stretches from the layout of cities to the composition of the atmosphere.
A New Model for Manufacturing
The internal combustion engine didn’t just power vehicles. Building those vehicles at scale forced an entirely new way of organizing work. Between 1910 and 1914, Ford’s Highland Park factory pioneered what became known as mass production: standardized parts, single-purpose machines, and a moving assembly line where each component followed a predetermined path through the plant. The system produced the Model T in volumes no craft workshop could match, and it became the template for factories worldwide.
The labor consequences were immediate. At the end of the nineteenth century, skilled craftsmen made up about 40 percent of the manufacturing workforce, with partially skilled operators and unskilled laborers each accounting for roughly 30 percent. By 1917, unskilled specialists made up over 55 percent of Ford’s workforce. Workers no longer shaped parts by hand. They fed pieces into machines, flipped a switch, waited for the automatic stop, then passed the piece along. As one Ford worker put it: “The machine is my boss.” This shift replaced American-born and northern European craftsmen with southern and eastern European laborers willing to take the new repetitive roles, altering the social fabric of industrial cities in the process.
The ripple effects went far beyond Detroit. The principles of standardization, interchangeable parts, and line production spread to virtually every manufacturing sector, establishing the work rhythms and factory hierarchies that defined twentieth-century industrial life.
Suburban Expansion and the Reshaping of Cities
No technology stretched city boundaries faster or more randomly than the car. Railroads and streetcars had already pulled populations outward along fixed corridors, but the automobile let developers build subdivisions anywhere a road could reach. Paired with new highways and the extension of electricity, the car made it practical to live miles from a metropolitan center and still hold a job downtown.
The communities that resulted were designed for driving, not walking. Drive-in markets, drive-in movie theaters, and even drive-in churches appeared. Shopping malls represented perhaps the clearest commitment to automobile-centered life on the urban periphery, pulling retail establishments, office buildings, and entire industries out of core cities. Even the architecture of homes changed. The garage became as essential a feature as the kitchen or the living room, built into the house and, increasingly, into the culture of the families who owned them.
The result was a landscape where living, working, and shopping were physically disconnected from one another, linked only by roads and highways. American cities and suburbs became utterly dependent on the car for nearly every daily activity. That dependency persists: the places most Americans live today were literally built around the internal combustion engine.
Agriculture and the Decline of Farm Labor
Before gasoline-powered tractors, farming depended on horses, mules, and human muscle. The internal combustion engine changed that equation. Early tractors handled plowing, and design improvements during the 1920s extended their use to cultivation, making them appealing for a much wider range of tasks. Machines gradually replaced draft animals, and each tractor could do the work of many laborers.
The effect was a massive migration away from agricultural work. As fewer hands were needed to grow the same amount of food, millions of people left rural areas for cities, fueling the urbanization that defined the twentieth century. The land once used to grow feed for horses and mules could now grow crops for human consumption or export, further boosting agricultural output.
Trucking and the Modern Supply Chain
For most of the nineteenth century, moving goods overland meant railroads. Trains were fast and cheap over long distances but locked to fixed routes and schedules. Trucks powered by internal combustion engines introduced flexibility. A truck could pick up goods at a factory door and deliver them to a store across town or across the country, on any road, on any schedule.
During the 1960s, goods distribution shifted decisively from rail to trucking. This made it possible to transport time-sensitive raw materials, parts, and finished products efficiently over long distances without waiting for rail connections. The modern supply chain, with its just-in-time deliveries and next-day shipping, is built on that flexibility. Virtually every product you buy in a store arrived there on a truck at some point in its journey.
Highways as Economic Infrastructure
The internal combustion engine created the demand for road infrastructure on a scale no previous technology required. The Federal-Aid Highway Act of 1956 authorized construction of the Interstate Highway System at an estimated cost of $27 billion (roughly $300 billion in today’s dollars). During the congressional debate, no one questioned whether the system was needed. The only argument was how to pay for it.
That investment never stopped growing. By 2000, all levels of government were spending $17.1 billion annually on Interstate capital improvements alone, a figure that represents about a quarter of total highway spending across all road types. Between 2000 and 2002, Interstate capital investment jumped 21.6 percent, nearly double the growth rate for roads overall. These highways didn’t just move cars. They connected labor markets, enabled long-distance trucking, and turned previously remote areas into viable locations for housing and industry.
Traffic Deaths and the Cost of Speed
The human toll of the internal combustion engine arrived almost immediately. U.S. traffic fatalities rose from 26 in 1899 to over 12,000 by 1920. By 1930, the annual death toll exceeded 31,000. By 1937, it reached nearly 38,000. These numbers climbed in rough proportion to the number of vehicles on the road, prompting entirely new categories of law, infrastructure, and public health intervention.
The fatality rate per miles driven did improve over time, dropping from about 24 deaths per 100 million vehicle miles traveled in 1921 to around 11 per 100 million by 1939. That decline reflects the introduction of traffic signals, speed limits, lane markings, and other safety measures that simply didn’t exist before cars. But the sheer volume of driving meant that total deaths kept climbing even as roads became safer per mile. The tension between mobility and safety has been a defining public health challenge ever since.
Carbon Emissions and Air Quality
The environmental cost of the internal combustion engine is now its most consequential legacy. In 2023, gasoline and diesel consumption by the U.S. transportation sector produced roughly 1,489 million metric tons of carbon dioxide, about 31 percent of all U.S. energy-related CO2 emissions. Gasoline alone accounted for 22 percent of the national total. The transportation sector as a whole was responsible for 39 percent of U.S. energy-related emissions, and about 80 percent of that came from cars and trucks burning gasoline and diesel.
These numbers represent just one country. Globally, the pattern repeats wherever internal combustion vehicles dominate transportation. Beyond carbon dioxide, engine exhaust produces nitrogen oxides, particulate matter, and ground-level ozone, all of which degrade air quality and contribute to respiratory disease. Cities built around car traffic tend to have measurably worse air than those with robust public transit.
The Engine’s Dominance Today
Despite growing investment in alternatives, the internal combustion engine still powers the overwhelming majority of the world’s vehicles. By the end of 2024, the global electric car fleet reached almost 58 million, roughly 4 percent of the total passenger car fleet. That number has tripled since 2021, but it means about 96 percent of passenger cars on the road still run on gasoline or diesel. When you include trucks, buses, and commercial vehicles, the internal combustion engine’s share is even larger.
The engine that Nikolaus Otto and Karl Benz helped develop in the late 1800s didn’t just create a new machine. It created a new world: one organized around personal mobility, cheap freight, suburban homes, and fossil fuel consumption. Whether that world is now transitioning to something different depends largely on how quickly the 96 percent becomes something smaller.