The Capital Beltway by Sean Emerson .

In the spring of 2019, a tanker truck overturned on the Capital Beltway near the American Legion Bridge, spilling fuel across the highway. The resulting cleanup shut down the Beltway for 12 hours, and commuters across Maryland, the District of Columbia, and Virginia expressed their frustration on social media as traffic spilled over onto side streets miles away.

Every day, over 200,000 vehicles travel on the Beltway in Montgomery and Prince George’s counties, and another 200,000 use I-270 in Montgomery and Frederick counties, making the two roads the busiest in Maryland. Major crashes like this aren’t an everyday matter, but they happen frequently enough for people to take notice: in 2019, trucks on the Beltway and 270 spilled magazines, potatoes, and Hershey’s chocolate.

The resulting congestion, and the hours that commuters lose, inevitably lead to calls to widen these roads. Yet this approach can actually create more problems than it solves, while ignoring the underlying causes of congestion. In the coming weeks, we’ll look at why simply building more roads won’t solve our traffic problems, and the mix of strategies that will actually reduce congestion, strengthen our communities and our economy, and protect our environment.

The costs of building more roads

Local and state officials have studied widening the Beltway and 270 basically since both roads were last widened in the 1990s, including a recent proposal to add up to four toll lanes to both roads. While there have been multiple proposals, they all have one thing in common: the assumption that driving rates will continue to rise uninterrupted.

As a whole, Marylanders are driving more than they were a few years ago, but that can vary from one part of the state to another. Montgomery County grew by 200,000 people since 2000, but vehicle miles traveled per capita - a measure of how much individual people drive - has actually gone down.

Since the inception of the Interstate Highway System in the 1950s, Maryland built an extensive network of highways. They opened up land for generations of population and economic growth, which made our state the wealthiest in the nation. But since then, the vast majority of the state’s transportation investment has been in roads. This imbalance has made driving the only convenient travel option at the expense of everything else, which has serious consequences for our environment, our economy, and our society.

If the question is how do we reduce traffic congestion, the answer will usually involve building more highways. Perhaps we should ask whether can we afford the costs of building more highways:

Cost #1: Rising seas and more flooding

Transportation is the leading contributor of greenhouse gases in Maryland, making it a primary contributor to climate change. As a result, outlying suburban areas where people have to drive more have the largest carbon footprints in the state, and continuing this pattern of development will speed up the worst impacts of climate change, like flooding. Our state has 3,100 miles of tidal shoreline, all of which are vulnerable to rising tides. Cities like Annapolis and Baltimore that saw only a few days of “nuisance” flooding each year now flood 40 times each year, and by 2100, they could see daily flooding, leading to property damage. Elsewhere, sea level rise could destroy wildlife habitats and farmland, and eliminate Maryland’s beach communities, a key source of tourism.

Cost #2: An endless cycle of sprawl and traffic

Between 1973 and 2010, one million acres of forest and agricultural land were consumed by development - an average of 74 acres per day. As our communities grow more and more spread out, people have to travel longer distances for daily needs, like schools, jobs, shopping, health care, recreation, or social activities, and driving becomes the only feasible way to make those trips. This results in more traffic congestion, which leads to more highway construction, which opens up land on the region’s fringe for development, beginning the cycle over again.

Cost #3: A stunted economy

Highways lead to spread-out development due to their large scale, which in turn costs local governments more to build because everything needed to serve it, like sewers and electrical line, must cover a greater distance. A survey of development studies around the United States found that sprawl neighborhoods cost 38% more to build than compact neighborhoods, while generating one-tenth the tax revenue, meaning that this pattern of growth actually puts local governments in debt. Over time, this can create a vicious cycle: as each new suburb is built, they effectively borrow from older places to cover their costs, drawing taxpayer money away from the region’s core out to the edge.

Cost #4: More displacement and segregation

Commute time is the biggest factor in someone’s ability to climb the economic ladder, according to a New York University/Harvard study. Yet many highways in Maryland were routed through or next to lower-income communities, effectively locking in racial and socioeconomic segregation with a physical barrier to jobs, shopping, and other daily needs, particularly for people without cars. Combined with land-use laws that favor greenfield development over infill construction, these roads pull investment from close-in communities to new suburbs on the region’s fringe.

While changing demographics and a growing interest in urban living has created immense pressure for housing in close-in neighborhoods throughout the Baltimore-Washington area, there’s now a severe shortage of housing in close-in areas, resulting in rising home prices and displacement. The University of Minnesota found that 33,000 people in the Washington area and 17,000 people in the Baltimore area have been displaced from the city and close-in suburbs to outlying communities far from jobs and transit, which only prolongs the cycle of poverty.

Cost #5: Worse public health

Over 500 people died on Maryland roads in 2018, including 133 people on foot, due to roads that are designed to move lots of traffic at high speeds. Meanwhile, people living next to highways have worse health outcomes due to pollution from passing traffic. The American Lung Association notes that people who have long-term exposure to traffic air pollution have a much higher risk of cancer, heart disease, diabetes, asthma, and even dementia. This not only includes emissions from internal combustion vehicles, but electric vehicles, which can still kick up dust that contains toxic metals, rubber, and other harmful compounds. While the risk is greatest for people living, or going to school, within 500 feet of a highway, air pollution can travel as far as one mile downwind.

Roads are an integral part of our transportation system, and will remain so for the foreseeable future. However, the current pattern of designing streets and communities around the singular goal of reducing traffic congestion ultimately weakens our state’s economy, sickens people, and makes our communities more susceptible to climate change. There’s another path, which we’ll introduce in subsequent posts.

This is the first in a series of articles, written by Dan Reed in partnership with the Maryland Sierra Club, on causes, impacts and solutions to traffic and transportation. All articles will be published on Greater Greater Washington.