Widening Roads Does No Favors for Denver’s Economy

It's old news that wider highways don't fix congestion, but a new study debunks the myth that the economic success of cities and suburbs depends on the unfettered movement of cars and trucks.

A boarded up house in the path of CDOT's I-70 widening. Photo: David Sachs
A boarded up house in the path of CDOT's I-70 widening. Photo: David Sachs

When highway builders want to convince people they need billions of dollars to build bigger roads, they rely on a trusted mantra: Without adding more space for cars and trucks, traffic congestion will suffocate the economy.

That’s what road boosters claimed about the $2 billion widening of I-70, which the chair of the Colorado Motor Carriers Association called “central… to the economy of our state.”

We shouldn’t fall for that argument, according to new research published in the journal Transportation by Wesley Marshall of the University of Colorado Denver and Eric Dumbaugh of Florida Atlantic University.

Their paper, “Revisiting the Relationship Between Traffic Congestion and the Economy,” shows that regions with healthy economies also tend to have high levels of traffic congestion.

“If your region is trying to widen an arterial (street) because they’re worried about it harming the economy, this study refutes that,” Marshall said. “If your city won’t tear down a freeway and turn it into a boulevard because they’re worried about congestion and the economy, this study refutes that.”

Marshall and Dumbaugh charted economic output, per capita income, and job growth against the intensity of rush-hour traffic congestion in 89 American metro areas over 30 years. They found that greater congestion did not lead to faltering regional economies. GDP and job growth actually increased in tandem with congestion, they found, while per capita income had no correlation.

“The cities that don’t have congestion… are the cities that are dying, in general,” Marshall said.

It’s important to realize that in the “congested” cities, people tend to have good options besides driving — and they use them. From the study:

Case in point: of the ten most congested cities in the recent Urban Mobility Report, seven of those cities rank in the top ten for lowest driving mode share. Eight of the top ten congested cities rank in the top ten for highest transit mode share, and four rank in the top ten for highest active transportation mode shares.

Problems arise when cities respond to rising congestion not by providing better transit, biking, and walking, but by widening roads, which just strands more people in traffic.

Is it possible to build so much road capacity that traffic delays dissipate? Only if you want to hollow cities out with highways and parking lots. “They wouldn’t function how we want urban places to function,” said Marshall.

The resources that transportation agencies put into road expansion should instead go toward giving people a way to bypass traffic, investing in high-quality bus and train service, and infrastructure for biking and walking.

“The never-ending cycle of widening is to some extent what we’ve been doing for many years,” Marshall said. “But what this study says is that you can’t sell that as an economic benefit anymore.”

  • LazyReader

    Instead of spending billions on light-rail or billions widening a highway they can easily reduce congestion just spending a few million on TV ads and billboards encouraging people to carpool.

    – charging single occupancy driver congestion fees in it’s most congested roads particularly during Rush Hour and use the money to repair their crumbling roads and bridges and tunnels.
    – Improve traffic signal coordination to move more vehicles per hour.
    – Deregulate the transit industry and allow people to use their cars to move people outside the scope of taxis
    – Convert the cities surrounding metro’s HOV lanes into HOV/HOT lanes
    – offer tax incentives for residents who use their cars to shuttle people.
    – Let private engineering firms build their own tunnels and toll lanes and charge people the right to use them.
    – Encourage urban cycling, 1,000 cyclers means 1,000 fewer cars

  • TakeFive

    That’s some funky logic they employ. It should remind that whenever anybody uses correlation to insinuate causation red flags should go up as to whether that dog can really hunt? Usually he’s a worthless mut.

    • Camera_Shy

      I look at it this way: what if 80% of the things I need a car for were all within 1 mile of my home? Then, the 20% of things I need a road or highway for could more easily be provided by transit. Or at least the city could spend the money it would have spent on highways I don’t need on transit I can use. I (personally) wouldn’t need a highway, let alone a widened highway. One reason we need so many wider roads is because our cities are not laid out with this 80% rule of thumb in mind. I think this study tries to say that if cities were laid out better, we wouldn’t need to widen the roads, and widening the roads is going in the complete opposite direction. My $0.02

    • Camera_Shy

      Look at it this way: what if 80% of the things I need a car for were
      all within 1 mile of my home? Then, the 20% of things I need a road or
      highway for could more easily be provided by transit. Or at least the
      city could spend the money it would have spent on highways I don’t need
      on transit I can use. I (personally) wouldn’t need a highway, let alone a
      widened highway. One reason we need so many wider roads is because our
      cities are not laid out with this 80% rule of thumb in mind. I think
      this study tries to say that if cities were laid out better, we wouldn’t
      need to widen the roads, and widening the roads is going in the
      complete opposite direction. My $0.02

      • TakeFive

        It’s a good 2 cents at that and if we could jump in the time machine back to the 1950’s we’d do things much differently – hopefully.

        I spent the weekend in Summit County and was able to plan my trip (from Phoenix) without needing a car. Taking the Bustang into the mountains was waaay more pleasant than if I had rented a car. There’s a lot to be said for better organized neighborhoods and MUCH better transit. It will take time and unfortunately good transit is very expensive to create and maintain even if worth the effort.

        At my social gathering in Silverthorne of ~70 people I was likely the only person that was the least bit interested or sympathetic to ‘urbanism.’ My nephew who lives in Wash Park can’t wait for Central 70 to get started. For people all along the I-70 corridor on the Western Slope, I-70 is a critical piece of infrastructure for their own lives and livelihoods. Different strokes…

        • Camera_Shy

          I agree with most everything you say, but with regard to it being the 1950’s I’ll play devil’s advocate a bit here…the cities and people all along the I-70 corridor on the western slope are at the point where today they can make decisions that will affect their build-outs such that in 50 years they don’t look back on these same issues and say, “gee if it were only 2020, we could have done things much differently (i.e. with a better result).” Are they doing it? And why is the fact that we (Denver) didn’t do it 50 years ago relevant in deciding what we do for the present and future? There will always be a point in time where people decide they should have done things differently, but just because they didn’t doesn’t mean they can’t effect change going forward. Again, my $0.02

          BTW, the Summit Stage is by far the best transit system within 100 miles (maybe 250) of Denver! We use it every time we go to Summit county. Free for everyone, takes up to 3 bikes on the front of the bus, and a free bus locator app to boot!

          • TakeFive

            Summit Stage was awesome. I arrived in Frisco about 4:50 pm and literally walked a few feet from my Bustang bus to the Silverthorne shuttle. At the Silverthorne transit station it was about 4-block walk to my hotel, the Silver Inn which is run by a couple from Poland who’ve had the hotel for 20 years. Nicest people in the world. My return trip to Denver was nearly as smooth with a 45-minute wait in Frisco.

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