Expanding highways and building more roads actually makes traffic worse

It’s a great time to be a road builder in the United States, and a terrible time to be a road user. If it feels like you’re perennially stuck in traffic due to road construction, you’re not wrong, and you’re not alone, according to a new report by Transportation for America.

The nation’s largest 100 urban areas added 30,511 new lane-miles of roads between 1993 and 2017, according to the report, a 42 percent increase (and a trend that shows no signs of slowing down). For perspective, that’s higher than population growth, which was 32 percent in those metros over the same time period. That’s not all that grew: traffic congestion, as measured in annual hours of delay, actually rose during those 24 years, by a staggering 144 percent.

The report, called The Congestion Con, explores the recent history of road-building in the United States, and argues that if anyone hopes this kind of massive infrastructure investments will help solve city congestion and traffic woes, this is far from being the case.

The report breaks down exactly why expanding roadways has been such a bad deal for the country. There’s the expense, for one. Each lane-mile of road costs between $4.2 and $15.4 million to build and an $24,000 a year to maintain. States alone spent $500 billion to expand roads between 1993 and 2017.

Second, it’s guaranteeing more of the same, in terms of roads, repair costs, pollution, and congestion. It’s the theory of induced demand: Building more roads and adding more lanes gives the appearance of speeding up traffic. But by encouraging sprawl, it spreads out stores, houses, and jobs, providing more reasons to drive more place and expanding many people’s commutes. It also adds more capacity, which is almost immediately filled up with more cars. Research by Kent Hymel of California State University of Northridge found that adding one percent more road capacity produces the exact same increase in the amount of vehicle miles traveled.

It seems logical that when populations grow, cities need to expand their transit networks. But comparing road building, congestion, and population growth statistics suggest that even when cities build roads at a faster clip than population growth, congestion still gets worse. During that same 1993 to 2017 period, San Diego roads expanded at about the same rate as population, yet the city still saw a 175 increase in congestion. And even in cities where roads were built much faster than new drivers arrived to fill them, congestion skyrocketed as well. In Pensacola, Florida, and Omaha, Nebraska—which both saw highways expand three times faster than population growth—congestion increased by 233 and 231 percent, respectively. In booming Boise, Idaho, roads expanded 141 percent while population grew 117 percent. But congestion increased 446 percent.

The increase in congestion on new, bigger roads is, in part, because it keeps people reliant on cars, as the report notes, “creating greater distances between housing and other destinations, and forcing people to take longer and longer trips on a handful of regional highways to fulfill daily needs.” The average driver puts in 4 more miles a day behind the wheel in 2017 than she did in 1993. Combine that with an affordable housing crisis and land-development patterns pushing more and more Americans to live further from downtowns and their jobs, and you have a formula for more crowded and congested roads.

The status quo, a treadmill of sinking money in roads only to see diminishing returns and more spending, looks even more irresponsible compared to a smarter, long-term regional investment in transit infrastructure. The Seattle metro area has embarked on an extensive plan to expand and invest in its light rail systems and bus network over the last decade, adopting initiatives like the Seattle Transportation Benefit District (STBD) funding scheme, and has seen promising results. The percentage of metro area trips taken on buses between 2010 and 2017 has increased from 42 percent to 58 percent, while trips in single-occupancy cars have declined from 35 to 25 percent. More buses and fewer solo commuters means fewer vehicles on the road. At the same time the city has been growing at a fast clip, adding 116,000 people between 2006 and 2019, car traffic has actually decreased, and mass transit ridership has shot up 89 percent.

It’s also been relatively cost-effective; for every dollar raised by STBD, $0.86 goes towards adding bus more bus trips. Seattle’s $54 billion Sound Transit 3 plan, a 25-year initiative which will levy increased sales, car, and property taxes over 25 years, is a lot of money. But when you compare it to the inefficiency of expanding roads and highways, and the added value of quicker and more accessible commutes, and the increase in value of transit-adjacent real estate, it looks like an smart investment.

Seattle isn’t perfect. And there’s much more it, and other cities, could do, as the report suggests: focus on mass transit efficiency (such as increasing the use of bus-only lanes and bus rapid transit) and routes that gets people to jobs and opportunity, redirect funding for new roads towards maintenance, increase walkability, focus on congestion pricing as a solution to traffic, and allow infill development and denser housing in cities.

But for the most part, transportation planners are sticking to the existing system. Houston is in the beginning stages of a $7 billion project to widen its I-45 freeway. Austin may see $4.3 billion spent on widening a highway that runs right through the center of town. Orlando is in the midst of its own $7 billion roadway spending spree, a plan to widen Interstate 4. A new 11-mile, four-lane highway project near Omaha, Nebraska, expected to cost $352 million, just broke ground.

Without fundamental changes to how we design our transit systems, we will just continue throwing good money after bad again, and expecting the results to be different. In Nebraska, road engineers predict that the hundreds of millions being spent on that strip of asphalt will result in just a 0.07 percent decrease in vehicle-miles traveled. That admission of the stalled status quo is almost as enraging as being stuck behind a semi truck during rush hour.