It doesn’t take long to convince someone sitting in traffic to start thinking about stopping for fast food. In a new study, researchers found that just 30 seconds of delay per mile was enough to spike an increase in fast food stops. Add in a longer traffic slog and you’ll up the drive-thru window visits.
“If there’s traffic between 5 and 7 p.m., which happens to be right around the evening mealtime, we see an increase in fast food visits,” Becca Taylor, assistant professor in the Department of Agricultural and Consumer Economics at the University of Illinois and study author, said in a statement. “Drivers have to make a decision about whether to go home and cook something, stop at the grocery store first, or just get fast food.”
Fast food wins out more often when the traffic slows.
In the study, publishedin the Journal of Urban Economics, the team analyzed data from Los Angeles County—one of the worst areas in the world for traffic congestion—and found that unexpected traffic delays beyond the usual congestion led to a 1% increase in fast food visits. “That might not sound like a lot, but it’s equivalent to 1.2 million more fast food visits per year in L.A. County alone,” Taylor says. “We describe our results as being modest but meaningful in terms of potential for changing unhealthy food choices.”
The team accessed daily highway traffic patterns for more than two years in Los Angeles. They cross-referenced that data with cell phone users searching for fast food restaurants in the same period. The team matched daily store-specific foot traffic data traced via smartphones to highway traffic congestion and then created a computational model showing a causal link between unexpected traffic slow-downs and fast food visits.
“It might not be intuitive to imagine what a 30-second delay per mile feels like,” Taylor said. “I think of it as the difference between 10 a.m. traffic and 5 p.m. traffic.”
Broken down into hourly chunks, the team noticed that a “significantly greater” number of fast food visits occurred when those delays coincided with the evening rush hour. And with traffic woes part of every big city—and fast food options lining major freeways across the country—the study points to traffic as just one more cause of unhealthy food choices.
The study authors also wrote that on days when highways were more congested, folks were more likely to frequent fast food and less likely to hit up a grocery store.
“Our results contribute to the literature suggesting time constraints are really important to the food choices people make,” Taylor said. “Any policies aimed at loosening time constraints—and traffic is essentially lost time—could help battle unhealthy eating.”
When data showing slow traffic leads to unhealthy food choices gets combined with evidence that increased traffic delays reduces physical activity, the study authors believe that “more time spent in traffic leads to worse weight-related behaviors.” By that the authors mean more trips to the drive-up window of a fast food restaurant.
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