On my fourth day in a semi-driverless car, I finally felt comfortable enough to let it stop itself. Before then, I’d allowed the car — a Volvo S90 sedan — to steer around gentle turns, with my hands still on the wheel, and to adjust speed in traffic. By Day 4, I was ready to make a leap into the future.

With the car traveling 40 miles an hour on a busy road in the Washington suburbs, I pushed a button to activate the driverless mode and moved my foot away from the brake and accelerator. The car kept its speed. Soon, a traffic light in the distance turned red, and the cars in front of me slowed. For a split second, I prepared to slam on the brake.

There was no need. The cameras and computers in the Volvo recognized that other cars were slowing and smoothly began applying the brake. My car came to a stop behind the Ford ahead of me. I began laughing, even though no one else was in the car, as my anxiety turned to relief.

If you’re anything like most people, you’re familiar with this anxiety. Almost 80 percent of Americans fear traveling in a self-driving car, a recent poll found.