Tesla's new Navigate on Autopilot technology can do amazing things but, even with all the car's cameras, sensors and computer brains, you'd better keep your eyes on the road because, seriously, there are crazy people out there.

On a highway, the Navigate on Autopilot software feature can take over most of the driving. Available on all properly equipped Teslas, it allows a car to change lanes on its own and even drive through highway interchange ramps itself while the driver's hands just hold the steering wheel. During a recent test drive, though, I was reminded that human intervention can still be needed. A street sweeper drove up onto the highway and crossed three lanes of traffic, nearly clipping the front bumper of a Model 3 I was riding in. The Tesla representative in the driver's seat hit the brakes.

Sure, the Tesla Model 3 might have braked on its own in time to avoid a collision, but neither of us wanted to try that experiment. Most of the time, though, the car was largely driving on its own. Our hands were on the steering wheel as we took turns driving back and forth between two locations in New Jersey but, as long as we were on a highway, the car was doing most of the work.

The Model 3 wasn't just holding its lane. It was changing lanes and even driving along exit and entrance ramps as we went from one highway to another, all without having to prompt it. The car was following its own navigation route to our destination.

I'm used to checking the navigation screen as I approach an exit ramp, trying to judge when I should move over into the slower right lane. If I move over too soon I waste time in slow traffic. If I wait too long I risk missing the exit.

With Navigate on Autopilot, the car makes the decisions. Punch in a destination and as soon as you enter a highway — the system only works on highways — the car can begin changing lanes and maneuvering through interchanges to follow that route. You can keep your feet entirely off the pedals. You can take your hands off the steering wheel, too, for brief periods, but the car won't change lanes or go down an exit ramp without your hands on the wheel.

There are a number of settings you can choose according to how comfortable you are with letting the car take over. You can require the system to "ask" you before changing lanes or, as I did, you can set it to change lanes without prompting you for permission first. You'll still be alerted with steering wheel vibrations, sounds, or both before a lane change happens but the car won't wait for you to OK it.

With Navigate on Autopilot, a Tesla car can change to a faster lane on its own.

It will wait for an opening in the next lane, of course. The car will even slow down or speed up (up to the maximum speed you've set) to get to an open spot it can safely merge into.

Like most humans, Navigate on Autopilot will also change lanes if the one you're in is just moving too slowly. That feature can be disabled or set to various degrees of aggressiveness all the way up to "Mad Max." The " Mad Max " setting will not fire a rocket to blow up the car in front of you. It will, however, change lanes automatically even if the other lane is going only a little faster.

Tesla TSLA None of this will work in the rain, though. All the features of the older and more familiar Tesla Autopilot system will continue to work in a downpour. You can even request a lane change by using the turn signal stalk and the car will do it. But, in a commendable display of caution,decided that Navigate on Autopilot will, for now at least, be disabled when there's rain. Water droplets can foul the camera lenses so the car's decision-making capabilities are curtailed.

We had to delay our test drive to allow a shower to pass, but after we were all done and I was driving home in a crossover SUV without any of this technology, I found that I missed it. I was back to having to choose lanes and get onto exit ramps myself on boring northern New Jersey interstates. I love driving, but it was great to have the help.

I do worry about Navigate on Autopilot, though. More accurately, I worry about putting this sort of technology into the hands of people who will over-trust and abuse it. Yes, there are some disclaimer paragraphs when you enable the system. It looks like the same sort of legal language I routinely ignore when updating my smartphone.

As you're approaching the exit ramp off the highway, the system begins alerting you that it will turn off in 600 hundred feet, then 500 feet, etc. Yes, there are steering wheel vibrations and tones, but the actual text warning you of this is pretty small. It seems to me that it should be big and probably flashing. Basically, every warning and disclaimer should be phrased and sized to be clearly seen and understood by the biggest bonehead conceivable.

Because it's that bonehead who will fail to understand that this is not a self-driving car. It's a car that helps you drive. I worry that a lot of people will have trouble keeping that straight.