If you drive northeast of San Antonio for about 180 miles, you will arrive in College Station, home to Texas A&M and its Transportation Institute (TTI). If you had made that drive back in April, while the Lone Star State was in lockdown under Gov. Gregg Abbott’s orders, the highways would have carried far fewer cars, pick-ups, SUVs and commercial trucks than normal.
Traffic levels were dramatically down in San Antonio, across Texas and the rest of the nation, and around the world.
However, a recent study by TTI determined that contrary to what might be expected, clearer roads were not found to be safer roads.
How can that be?
TTI researchers crunched the data and found that there was a nearly 50 percent drop in motor vehicle crashes in Texas in April. Using a bit of logic and math, you might assume that if crashes are cut in half, crash fatalities would likewise be halved – but that assumption is wrong.
TTI found that the proportion of those crashes that were fatal rose by 50 percent. This meant that there was only an overall drop of 20 percent in traffic fatalities.
Analyzing urban Texas and rural Texas
The Texas A&M researchers studied the data for both urban and rural areas of the state, dividing the crashes into several categories:
- All single-vehicle crashes
- All multi-vehicle wrecks
- Urban multi-vehicle crashes
- Urban single-vehicle wrecks
- Rural single-vehicle crashes
- Rural multi-vehicle wrecks
Examining the results
The numbers of both multi- and single-vehicle crashes dropped by 55 percent and 23 percent, respectively. Yet the proportion of wrecks with at least one fatality rose by 14 percent in single-vehicle crashes and 59 percent in multi-vehicle collisions.
TTI Senior Research Engineer Robert Wunderlich said the study helps us understand the effects of the pandemic on traffic safety, showing that the risk of death or injury is actually greater when roads are clearer.
Wunderlich said two main factors affect traffic accidents: exposure and risk. Exposure is simply the amount of travel, while risk is the chance that travel results in a wreck, injury or death.
Exposure was down in April because there were fewer drivers on Texas roads, so there were fewer crashes. Because the fatal crash rate dropped by only one-fifth during the month, the risk of a fatal wreck was actually greater than normal.
Another crash factor: speed
Wunderlich said that speed is one of the primary determinants of crash severity. He said a 10 percent reduction in speed produces 38 percent fewer fatalities and 27 percent fewer serious injuries.
But his research team found that average speeds on Houston freeways rose from 45 mph normally to 65 mph in April.
“So all crashes occurred at higher, yet legal, speeds,” Wunderlich said. So even though there were fewer crashes, they happened at higher average speeds, which sends the serious injury and fatality rates soaring.
Simple safety formula
The research engineer said the formula to reducing the number of crashes – and the severity of the crashes that do occur – is simple: “Basically, we reduce our risk when we slow down, pay attention and stay sober,” adding that “the best way to reduce risk is the old-fashioned way: by making safer choices.”