Roadways exist as part of an ecosystem—an important consideration when planning traffic and pedestrian safety.
“We are often subject to forces that are way beyond our control,” says David Leuer, state traffic engineer for MnDOT’s Office of Traffic Engineering. Road safety, he says, is heavily influenced by road design, which in turn is influenced by land development and the historical and cultural forces that shaped it.
As part of Minnesota Toward Zero Death’s “Traffic Safety Hotdish” series, Leuer gave a webinar presentation on the history of land development in the American South and how innocuous-seeming details—such as the advent of air conditioning—could have contributed to some of the most dangerous roads in the US.
The American South, prior to the 1950s, had been experiencing a steep population decline. Between 1910 and 1970, the Great Migration saw African Americans leaving the South in record numbers—around 6 million people—to escape poverty, lynching, and Jim Crow laws.
Starting in the 1950s, Leuer says, that process began to reverse itself. The passing of the Civil Rights Act of 1960 and the Voting Rights Act of 1965 ended the legal sanctions of Jim Crow laws, and cheap, undeveloped land began to draw people back.
In addition, air conditioning was becoming cheap enough to be commercially available for private homes, which meant that houses could be mass produced without needing to prioritize airflow or shading.
Between 1950 and 2020, the population in the South more than doubled, according to the US Census Bureau. Around 38 percent of the US population currently lives in the South—making it the most populous region in the country.
“That represents millions upon millions of people moving to the South at a much greater rate than was anticipated,” Leuer says. “This extreme growth led to development at an epic and—even more importantly—unprepared scale. Cities, counties, and states were largely just not ready for these big movements of people coming into their region.”
The big problem that arose as a result of this rushed development was a lack of careful access management, Leuer says. Access management refers to the process of granting private businesses or homeowners vehicular access to roads. When done well, it prioritizes safe and smooth traffic flow. It generally aims to separate fast moving traffic (such as interstates) from roads where there are lots of conflict with pedestrians or turning cars (such as residential roads).
In Minnesota, Leuer says, development and road construction occurred relatively slowly, and transportation officials have been able to prioritize safe movement of traffic when managing access. Developers are granted access in accordance with a hierarchy that separates fast-moving traffic from conflict.
In the South, by contrast, fast development was largely prioritized over safe access management.
“For a lot of elected officials, traffic safety really isn’t on the top of their mind because they don’t understand the issue between access management and safety,” Leuer says. “They see the development and they know development looks good.”
Fast, multilane highways began intersecting with businesses, apartment complexes, and private residences, leading to street-road hybrids (nicknamed “stroads”) with lots of potential conflict between fast traffic, turning vehicles, and pedestrians.
One of the worst examples is US Highway 19 in Florida. From 2017–2022, 48 pedestrians were killed on this one stretch of roadway, making it the deadliest highway for pedestrians in Florida.
“This thing has a lot of access points and it has a lot of crashes,” Leuer says. “This was an area that had a lot of growth, and that growth was likely linked to the air conditioner.”
Trying to fix these problems is difficult once they’re established, Leuer says. Once granted, access is very difficult to revoke, and most remediation strategies—such as upgrading highways to interstates, adding crosswalks and pedestrian lights, or separating pedestrians from roads with bridges and sidewalks—are usually either prohibitively expensive or ineffective.
Careful development needs to be taken into account early, Leuer says.
“Access management, land development, and traffic safety are all really intricately linked, and linked way more than people probably realize,” Leuer says. “Let’s try to make sure that it happens in the right way and in the right place and at the right time.”
—Sophie Koch, contributing writer
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