Motor vehicle crashes cost the US $242 billion a year, according to the most recent estimate.

 A study finds that California lockdown restrictions reduced crashes that kill or seriously injure people to 200 a day, down from 400 in the same period last year.

FOR ALL THE misery Covid-19 has wrought, the shelter-in-place orders imposed in the name of public health have yielded a few benefits, at least for driving. American motorists are putting half as many miles on their odometers as they usually do this time of year, according to Arity, a data analytics company. One result is reduced air pollution. Another is fewer crashes, saving lives and money. In California alone, those savings amount to some $40 million each day, well over $1 billion since the state went into lockdown mode in March.

That figure—presented in a new study by researchers at the UC Davis—is surprising only if you don’t consider the economic ripples of a crash. Counting medical expenses and productivity losses stemming from injuries and deaths, car crashes cost the US economy more than $75 billion in 2017. Throw in property damage, emergency responders, insurance costs, congestion, and the inevitable court cases, and it’s far more. In 2010, the most recent year for which the grand total is available, crashes cost the US $242 billion. California accounted for $20 billion of that sum.

 Yes, even that pile of money is but a molehill in the shadow of the mountain of economic devastation from the novel coronavirus, which has pushed 26 million Americans out of work and eaten through the $2 trillion Cares Act in a few weeks. But California’s $40 million-a-day savings is worth considering for at least two reasons.

First, it illuminates the often ignored price of relying so heavily on the personal car. About 86 percent of US commuters drive themselves to and from work, and in doing so live with the small but real risk of a crash that could kill, injure, or inconvenience them. By passenger-mile, moving by bus or train is one-tenth as deadly, or less, according to the National Safety Council.

Second, the savings stem from shelter-in-place orders, a novel government stratagem to control a pandemic. “Understanding how a policy is working is important to do as quickly as possible so you can enhance the positive impacts and try to reduce the negative impacts,” says Fraser Shilling, who codirects the UC Davis Road Ecology Center and wrote the report. “What’s the impact of the thing you made up on the fly?”

Shilling’s study covers California’s freeways for a period of just over three weeks, beginning March 22, a few days after the statewide shelter-in-place order took effect. Compared with the same period in 2019, traffic on those highways dropped by as much as 55 percent. Average vehicle speeds rose by about 4 mph, and crashes fell to about 500 a day, from 1,000. Two hundred thirty-seven people were killed or injured, down from 448 in the same period in 2019. Those decreases track with data Shilling pulled from four Sacramento-area hospitals, which saw a combined 38 percent drop in injuries to motorists and motorcyclists and a 46 percent drop in injuries to pedestrians and cyclists.

Arity’s national data looks similar. Based on info from 23 million drivers, it reports a drop of more than 50 percent in vehicle miles traveled. The biggest drops, over 60 percent, occurred in New York, New Jersey, and Michigan. More-rural states saw smaller changes: Driving dropped by less than 45 percent in Arkansas, Idaho, Kentucky, Utah, and Wyoming.

To calculate the savings from California’s newly safer roads, Shilling used formulas from the Federal Highway Administration, which account for things like property damage, lost time at work, insurance claims, and the monetary value of a human life. The result is a rough estimate, because it’s not clear how the current economic upheaval might change the math’s underlying assumptions. Congestion, for example, doesn’t cost as much now as usual, since fewer people are driving to work. But the costs are likely higher in California than they are nationally, thanks to the Golden State’s high cost of living. “There’s definitely wiggle room,” Shilling says. He thinks the actual savings are more significant. “This is a minimum.”

California tracks congestion more carefully than most states, but even its data fails to reveal who is still driving and where they’re going. Shilling’s study relied on data from the California Highway Patrol, which covers mainly freeways along with some major surface streets. That leaves questions about how much people are driving on surface streets. Presumably, some people are driving more than usual, perhaps because they are still working, are avoiding public transit, and no longer worry about sitting in traffic. As home deliveries of things like groceries spike, that means more driving on local roads.

The bigger questions, though, are what will happen once shelter-in-place orders are eased or lifted and whether the return to cars will erase the current air-quality and cost savings, says Alexandre Bayen, who directs the Institute for Transportation Studies at UC Berkeley. The average price of gas in California is $2.77 per gallon, compared with $4.04 a year ago. Nationally, filling up costs less than less than $2 a gallon. People will start taking trips they’ve been putting off for weeks. Those who have the option of driving are likely to avoid public transit, especially if bus and subway systems can’t provide enough capacity to keep riders spread out. Programs like the Bay Area’s Casual Carpool will likely drop in popularity for months, as people try to minimize close contact with strangers, Bayen says. “The hard part is the reopening.”

Via Wired.com