We know that wide streets like Federal Boulevard and Sheridan Boulevard, known as “arterials,” endanger people’s lives and act as barriers to physical activity and wellness. But it doesn’t have to be that way: New research suggests that arterials with lower traffic volumes, safe crosswalks, generous pedestrian infrastructure, and street trees perform better on several quality-of-life indicators. The challenge is transforming the streets.

University of Colorado Denver researchers Wesley Marshall and Carolyn McAndrews published their paper, “Understanding Livable Streets in the Context of Arterials that Surround Them,” in the Transportation Research Record earlier this year.

Graduate students gave 723 residents near wide Denver roads a 33-question survey covering topics like whether kids play in the street, if speeding or traffic pollution are problems, the ease of walking and biking, and the sense of community on the block.

Some arterials were classified as “high-design” (with street trees, generous medians, and sidewalks, a safe crossings) and others “low-design” (lacking those features).

The study found that the quality-of-life indicators on the survey are worse near arterials with more traffic volumes and “low-design.” People who live around high-traffic, pedestrian-hostile arterials are more likely to view them as boundaries, not as a part of the neighborhood.

“In other words,” the authors write, “a big, bad arterial detracts from the livability of nearby residential streets, whereas what could be a considered a good arterial (lower levels of traffic with a higher urban design quality) enhances livability.”

The irony is that these types of wide, dangerous streets, which are the site of a disproportionate share of pedestrian deaths, were meant to make life better for residents. The idea, about a century ago, was to push cars away from neighborhood streets. But those good intentions created a monster.

As cars proliferated and cities expanded, arterial roads morphed into highways that crisscross neighborhoods in Denver and other American cities. They’re filled with homes, bus stops, businesses, schools and other important destinations — in short, lots of people. Yet they’re not designed for people.

“As a traffic engineer myself, it’s honestly embarrassing to see streets like Colorado Boulevard or Federal Boulevard still in existence,” Marshall wrote in an email. “The funny thing is that despite focusing almost entirely on prioritizing cars, average travel speeds over those corridors are still so slow. The bottom line is that we can do better, and good arterials help make these streets better for everybody that uses them — as well as those living in the surrounding neighborhoods.”

So what does this mean in the context of Denver, where urban highways have divided and conquered the city?

For one, the Colorado Department of Transportation and Denver Public Works have to realize that prioritizing the movement of cars instead of people has serious negative impacts on people’s lives, Marshall says. He pointed to Octavia Boulevard, an arterial road in San Francisco, as an example of an arterial roadway that’s also designed to accommodate people on foot.

The city should also look to its street grid to disperse traffic. “Historically, the transportation profession has placed too much emphasis on single corridors,” Marshall said. “This has led to trying to solve what we think are our problems with bigger and bigger arterials, highways. The reality is that the overall network plays a much bigger role than we’ve given it credit for. Focusing on policies such as ‘complete streets’ is fine, but we aren’t going to get the outcomes we are looking for if we don’t have complete cities to support those complete streets.”