During the last major El Niño, when 7 inches of rain fell on parts of South Orange County in a single day, I was a know-it-all teenager. I remember poking fun at my parents when they insisted on driving me to a school function because of the inclement weather. I told them that they were being wimpy Southern Californians, and argued that elsewhere in the country, traversing icy roads and snowstorms were routine parts of winter living. Surely mere raindrops wouldn't hurt me.
My parents responded that they owned the family vehicles and would dictate who drove them. But if they had wanted to rebut me with hard data, they could have pointed out that more than 12% of fatal crashes in the United States occur on wet pavement, or that accident rates skyrocket in this region during almost every rainstorm.
The best available numbers are staggering. "In Los Angeles, fair-weather crash rates peak at 10 an hour for three hours in the early rush, but stay much lower through the rest of the day," John Metcalfe wrote last year in CityLab. "Meanwhile, accidents during rainy periods soar above 10 for more than half the day, approaching 15 per hour around 3 p.m."
It's not just teenagers who should stay off the roads during El Niño, it's everyone. Since that obviously won't happen, I propose the next best solution: When it rains in Southern California, all speed limits should automatically fall. I'm singling out Southern California because its residents aren't used to inclement weather; and focusing on speed because many kinds of accidents that happen more frequently in rain — those due to skidding, hydroplaning, and reduced visibility — can be avoided by slower driving.
Uncommonly enlightened drivers like you, dear reader, know that technically, the legal speed limit in California is whatever is posted or the maximum safe speed, whichever is lower. "You must drive slower when there is heavy traffic or bad weather," the California Driver Handbook states, as if all residents possessed the discretion to parse vague guidelines sensibly — which they don't.
We've all observed motorists who zoom down wet freeways at speeds that wouldn't even be safe in dry weather. We've all cringed at cars maintaining the same following distance behind us on puddle-strewn roads as they would on dry streets. During El Niño, I'm particularly cognizant of the best driving advice my father ever gave me: Presume every vehicle around you is piloted by someone totally lacking in common sense. I typically proceed as if everyone is either sexting their significant other or searching Yelp for the best place to buy replacement blades for their windshield wipers.
To reach oblivious motorists, we need more specific rules. Finland and Sweden impose lower general speed limits in wintertime. In France, in case of rain or snow, "the speed limit for motorways changes from 130 km per hour to 110 km per hour," according to the European Conference of Ministers of Transport. On rural roads there's a similar shift. In fog, the maximum speed on all roads is 50 km per hour.
And although there's a difference between making a rule and making people follow it, studies suggest that drivers really do slow down when lower speeds are posted on electronic signs.
In that spirit, here's what I propose: The speed limit in the five Southern California counties should be 10 miles per hour lower than usual when rain is falling or the road is still wet. And, while we're at it, drivers should be required to double the minimum following distance. These changes may not be sufficient in all cases, but at least they're clear, easy to remember, and of course far more specific than "drive slower in bad weather."
No rule can guarantee our safety. As in 1997 and 1998, El Niño is expected to bring flash floods, mudslides, downed trees, and surging surf. Still, in a region where few have experience driving in inclement weather, we can at least try to reduce the avoidable crashes.
Conor Friedersdorf is a contributing writer to Opinion, a staff writer at the Atlantic and founding editor of the Best of Journalism, a newsletter that curates exceptional nonfiction.