Last night I witnessed one of my worst nightmares.

I was driving home from our niece’s apartment (we’re taking care of her cat while she and her husband are away) heading north on one of Berkeley’s wider thoroughfares. I was in the left lane as the car ahead of me approached an intersection. I noticed an older man in dark clothes carrying a bag slowly across the crosswalk. “Does the driver in front of me see the pedestrian?” I wondered, and an instant later realized he didn’t.

There was a collision.

I saw the pedestrian’s bag of goods explode. The next thing I saw was the pedestrian on his side in the intersection, unconscious.

The risk manager in me sprang into action. I pulled over, took out my cell phone, and called the Berkeley Police emergency line. I succinctly explained what happened, and the dispatcher sent police cars and paramedics immediately. Then I got out of my car and guided traffic around the victim while others tended to him.

The police arrived quickly and took control. The paramedics came a couple of minutes later. Little time had passed, but when an officer asked what I saw, I had trouble remembering. Was the victim crossing east or west? What speed was the driver going? Did the driver have his lights on?

It all happened so fast . . .

I’m pretty sure the victim was walking east to west and the driver was going 20–25 miles per hour with his lights on. It seemed the victim never saw the oncoming vehicle, and the driver never saw the victim in the crosswalk. The driver, who remained on the scene, was an older man also. So two people, perhaps, with declining eyesight and alertness.

I’ve long feared being the victim or perpetrator of a motor vehicle accident. I always drive slowly — like an old man, The Fabulous Wife sometimes scoffs — and at night approach intersections with my foot over the brake, checking each corner for pedestrians before coasting through. That’s why I saw the victim. I was looking for him.

Because I don’t want to maim someone for life, as he most likely is.

I’m also terrified of being the victim of a negligent driver. Long before my University of California colleague Chris Patti was killed 16 months ago, I crossed streets at night like a squirrel sighting a dog pack.

Our president has shut down much of the federal government over the perceived threat of illegal immigrants. Last week an illegal immigrant allegedly murdered a police officer in the small town of Newman (on the way to Yosemite) and our president made it his number one argument for walling up the border.

My guess is that if you counted all the deaths and incapacitating injuries caused by illegal immigrants in this country over the last year, they’d come nowhere near the deaths and injuries caused by vehicle accidents. According to the National Highway Traffic Safety Administration, over 37,000 people were killed in accidents in 2016, and 221,000 people suffered incapacitating injuries.

Trump logic demands we wall people off from their cars.

Which, actually, isn’t the worst idea. I can’t wait for self-driving cars, prohibitively expensive fuel, and ecological necessity to make driving safer and less common. Vehicular mobility comes at a terrible price.

The root causes of auto accidents are inattention, impatience, and intoxication. We use the pejorative “drives like an old man” to signify someone creating risk due to diminished abilities (inattention), but also to signify someone creating risk by driving slower than “normal” (provoking impatience in others). I mitigate the first risk by embracing the second. But before you curse me for adding a few extra seconds to your trip, consider the toll impatience behind the wheel is taking on our society — please.

Former Risk Manager at UC Berkeley, author of four books, ectomorphic introvert.

Former Risk Manager at UC Berkeley, author of four books, ectomorphic introvert.