The Model 3 may not have the rocketlike acceleration of the X, but I found it nimble and responsive. I easily accelerated from a full stop into traffic flowing at highway speed, usually a nerve-racking maneuver in a conventional car. Driving the Model 3 was such a pleasure I was reluctant to cede any control to Autopilot.

For someone with decades of experience driving a conventional car, my first taste of semiautonomous driving last fall had come as a shock. The sensation of a vehicle moving on its own was so bizarre that I instinctively gripped the steering wheel, which immediately transferred control back to me.

This time I was more relaxed, willing to see how the car would behave. I gave the voice-activated navigation system a destination (Garden State Plaza, a New Jersey shopping mall about 20 miles away), and the car accelerated, braked, stayed in the center of the lane and maintained a comfortable three-car distance ahead of me, all without my intervention. At the mall, it detected an empty parking place, and flawlessly backed into it.

One of its most impressive features is the ability for the driver to change lanes simply by pressing the turn-signal lever. The Tesla scans for traffic in the adjacent lane, waits for an opening and then glides into place, eliminating the danger of a blind spot. (Over the years I’ve experienced several close calls involving lane changes and blind spots.)

Although I’d been briefed on its limitations, so successful was Autopilot that I was tempted to let down my guard by not bothering to look in the rearview mirror. That would have been a mistake.

For all its vision capabilities (including in darkness), Autopilot became confused when lanes weren’t clearly marked or split in two or at exit ramps. You can’t simply program the destination and let the car find its way. It’s reassuringly cautious about changing lanes, but in heavy traffic, I would have missed an exit while waiting for it to find a suitable opening, and had to assert manual control.

While heading south on the New Jersey Turnpike, I could see in the rearview mirror a BMW bearing down at high speed. I pushed the turn signal for a lane change, and despite its ultrasonic sensors, the Tesla seemed oblivious to the onrushing car. It started to move into its lane; the driver laid on his horn, and I had to grab control to avoid an accident.