Highways and motor vehicles are America’s great success story. The United States had more than 4 million miles of roads in 2019, of which 2.9 million were paved, making it possible for motor vehicles to get just about anywhere in the country (except, of course, Hawaii and the island territories).25 Americans enjoy more than 15,000 miles of automobile travel per capita each year, which is more than the travel by all modes combined by people of any other country on Earth.26
One of the factors that made automobiles so successful was that they could use existing infrastructure. By 1900 there were only about 8,000 automobiles in the country, but the nation already had more than 2.3 million road miles, which gave new auto owners plenty of places that they could go.27
For many years, major road improvements were paid for by user fees, thus creating a feedback relationship: the more people drove, the more money there was to spend on road building and maintenance, and hence, and better roads were available. In 1919, Oregon became the first state to dedicate gasoline taxes to roads, and by 1931 every other state had followed Oregon’s example. In 1956, Congress dedicated federal excise taxes on fuel, vehicles, and tires to roads, initially funding construction of the Interstate Highway System.
The interstates have proven to be the backbone of the nation’s transportation system. Although interstate highways comprise just 2.3 percent of total lane‐miles of U.S. roads, they support well over 25 percent of motor vehicle travel.28 Roughly 20 percent of all passenger‐miles, and nearly 20 percent of all freight‐ton‐miles, take place on interstate highways.29
Unfortunately, the feedback relationships between motor vehicle users and highway producers were weakened in 1982, when Congress began diverting 20 percent of all increases in federal gas taxes to urban transit. Many states followed suit: 19 percent of federal highway user fees and 28 percent of state highway user fees were diverted to nonhighway programs in 2018.30 The resulting shortfall in highway funds led Congress to supplement federal highway user fees with $51.9 billion in general funds in 2016, which were intended to cover a five‐year period. The use of general funds for highways further weakens the ties between users and producers.
These diversions correspond to the general shift from demand‐driven to supply‐driven transportation policy. Instead of improving the transportation system that people use the most, legislators are effectively taxing the users of that transportation system to fund systems that people hardly use. Nevertheless, America’s highway infrastructure is in excellent condition. Although the American Society of Civil Engineers’ infrastructure report card gives highways a D grade and bridges a C+ grade, these low grades are not supported by the actual data.31
The Federal Highway Administration requires states to regularly inspect bridges and highways. Bridges are graded to be in “good,” “fair,” or “poor” condition.
In 1992, out of the more than 600,000 highway bridges in the country, about 124,000 (20 percent) were considered to be in poor condition.32 Since that time, state and local governments have repaired or replaced most of those bridges so that, in 2019, only 46,000 (7.5 percent) of bridges were in poor condition.33
Only 2.2 percent of bridges owned by toll authorities were in poor condition in 2019. Some 5.3 percent of bridges owned by state highway authorities, which are largely funded out of fuel taxes and other highway user fees, were in poor condition. By contrast, 11.6 percent of bridges owned by city and county governments, whose transportation agencies are funded largely out of property or sales taxes, were in poor condition.34
Similar results are found by scrutinizing data regarding highway conditions. Highway engineers measure the roughness of pavement using an index in which a lower number corresponds to smoother pavement. The roughness index for all types of roads has steadily declined, indicating that road conditions are improving across the board. Moreover, the smoothest roads tend to be those that are owned by states or by toll road authorities, while roads that are locally owned (and therefore funded more out of tax dollars than user fees) tend to be the roughest.35
Agencies whose funding comes from tolls have a strong incentive to maintain their infrastructure because motorists often have a choice of routes and won’t pay a toll to drive on poorly maintained roads. Agencies funded out of other highway user fees have a similar incentive, although it is not as strong, while agencies funded out of taxpayer dollars have little incentive to keep their infrastructure maintained because their tax revenues will continue to come in even if their roads are in terrible shape.
While user fees result in better‐maintained infrastructure, there are several problems with using excise taxes to pay for roads. First, unlike income, sales, and property taxes, excise taxes do not automatically adjust for inflation. Since 1993, the last time the federal gas tax was increased, inflation has reduced the value of gas tax revenues by 43 percent. Second, fuel taxes do not automatically adjust for the use of fuel‐efficient cars, and since 1993 the average car has become 39 percent more fuel‐efficient.36
Third, and perhaps most important, fuel taxes do nothing to relieve congestion. Roads have a unique attribute: when they are full, their throughput declines. A typical freeway lane can move 2,000 vehicles per hour in free‐flowing traffic, but additional vehicles cause traffic to slow and throughput can decline to fewer than 1,000 vehicles per hour. This can generate several hours of stop‐and‐go traffic even if the number of vehicles seeking to use the lane exceeds 2,000 per hour for only a short time.
This is why urban highways continue to appear chronically congested even after road expansions: the roads are not utilized to their full capacity because few states have adopted any mechanisms for preventing users from trying to force too many vehicles on the roads. One way to relieve congestion is to build more roads, but this is inefficient because the roads will be used to just half their capacity during the times when demand is highest. Another way is to physically limit entry to the roads to ensure that they never exceed their rated flow capacity, but this would be expensive and controversial.
A third way would be to price the roads properly, which is also controversial. However, this controversy can be reduced if people understand that proper road pricing will effectively double the throughput of roads during peak periods. In other words, road pricing will not price people off the roads so much as it will price them onto the roads because it will increase the number of people who can use them during rush hour.
One way to improve road pricing is to completely replace gasoline taxes with mileage‐based user fees. Oregon and other states are experimenting with such fees.37 Congress could encourage more states to do so, perhaps by giving states with such programs a small increase in formula highway funds. Mileage‐based user fees will be especially controversial if motorists believe that the states will divert some of those fees to nonhighway programs, so to make such fees acceptable states should write provisions into their constitutions that require all such fees, along with vehicle registration fees and other highway user fees, to go only toward roads.
It is worth noting that the United States has about 67,000 miles of freeways, while China, in just two decades, has built 93,000 miles; it is building five new freeway miles a year for every mile built in the United States and paying for them with tolls.38 New freeways in the United States would not only relieve congestion, they would improve highway safety: the safest roads we have (measured by fatalities per billion vehicle miles) are urban freeways, while non‐freeway arterials are the most dangerous roads we have, so converting non‐freeway arterials to freeways would save thousands of lives a year.39 While we shouldn’t build freeways simply because China is building them, we should recognize what Chinese officials clearly understand: freeways improve mobility, increase safety, and boost general economic development by enabling travel and shipping that would not have taken place without them.
Automobile ownership is almost universal in America. Census data show that 91.4 percent of households have at least one automobile.40 In addition, 95.7 percent of workers live in a household with access to at least one automobile, and nearly a third of the 4.3 percent who don’t own a car nevertheless commute to work by automobile, either in a carpool or with a borrowed car (such as a vehicle supplied by their employer).41 Still, Department of Transportation data indicate that about 7 million low‐income households lack access to an automobile.42
Studies show that the best intervention for helping people out of poverty, as it relates to transportation, is by providing access to an automobile. “Car ownership is a significant factor in improving the employment status of welfare recipients,” say University of California–Los Angeles planners Paul Ong and Ellen Blumenberg.43 Helping the poor, say Yale economist Katherine O’Regan and University of California–Berkeley economist John Quigley, means “promoting the mass transit system that works so well for the nonpoor—the private auto.”44
One Portland study finds that people without a high‐school diploma are 80 percent more likely to have a job and earn $1,100 more per month if they have a car. In fact, the study reports that owning a car is more helpful to getting a job than getting a high‐school degree or equivalent.45 Another study by University of California researchers finds that closing the black‐white auto ownership gap would close nearly half the black‐white employment gap.46 A 2014 study published by the Urban Institute concluded that low‐income families with cars found better jobs, had better housing, and were less likely to fall back into poverty. The study urged that poverty programs be coordinated with “transportation programs in ways that enhance the upward mobility of low‐income households.”47
Automobile access works better at helping low‐income people than free transit services because automobiles give people access to more jobs and other economic opportunities, low‐cost consumer goods, and better housing. The University of Minnesota’s Accessibility Observatory finds that the typical resident of the nation’s largest urban areas can reach 44 times as many jobs in a 20‐minute auto drive as they can in a 20‐minute transit ride.48 Transit, incidentally, is so inconvenient that even a reasonably competent bicycle rider can reach more jobs in 50 minutes or fewer than someone spending the same amount of time on transit.49
For these reasons, some nonprofit groups have programs that help provide low‐income people with low‐interest loans specifically for buying cars. These groups find that auto loan recipients end up with more satisfying, higher‐paying jobs and reduce their dependence on various welfare programs.50 “Ownership of a private automobile is a key element of success in obtaining the ‘assets’ of independence: job training or education, a good job, health care, child care, social supports, and even self‐esteem and family/community relationships,” one study found.51
The pandemic has had an interesting effect on motor vehicle traffic. As of September 2020, total vehicle travel exceeded 90 percent of September 2019 levels. Yet, with millions of people working from home, there are no clear rush hours. Morning traffic is much lower than it was before the pandemic, while traffic between noon and 5 p.m. is higher than before the pandemic, and that traffic continues into the evening with no clear highest‐volume period. If large numbers of people continue to work from home after the pandemic, rush hour stop‐and‐go traffic may not be as serious a problem as it was before, but other factors will still contribute to road congestion. Whatever the future holds, more effective road pricing, such as variable‐priced toll roads or mileage‐based user fees, will still help prevent traffic slowdowns.