I’ve always wondered how accurate auto navigation systems like GPS really are. They’ve always seemed a little extravagant to me, and the thought of driving around with a computerized voice telling me how to get somewhere seemed a little too futuristic to be true. But that changed when I was on vacation recently and had the opportunity to use a rental car equipped with one of the new auto navigation systems.

I was in Florida where it can be impossible to find your way around, especially in the packed tourist cities like Orlando. We were staying on Disney property so my husband could attend a conference, so my days were free to explore the area. Being by myself, I didn’t want to get lost, so I figured it would be as good a time as any to do some research on auto navigation systems. I rented an Explorer with a GPS unit installed in the dash, and I immediately began to test it. I wanted to see if it could accurately lead me back to my hotel and to other short destinations that I already had the directions for. It did a pretty good job, though it got a little confused when I ignored a turn command on a one-way street and it had to figure out an alternate route.

And that’s the thing about auto navigation systems—as hard as they try to charade as a good human guide, they’re not human. They are flawed in the way that all machines are, and they can’t give you hints based on information that is happening right then in the front seat of your car. They can’t remind tell you to pay attention to where you’re going, or to check the street signs or make a quick turn, they can merely serve as a guide to the best of their programmed ability and you need to do the rest. Good auto navigation systems are like mapquest. Ninety percent of the time they’re accurate, but they won’t always give you the best way to get somewhere or provide you with up-to-the-minute information about road detours and other changes along the route.

I imagine the technology in auto navigation systems will only continue to improve, and the next generation may be able to sense when you’re about to screw up and make a mistake and will help you try to avoid it. Until then it makes sense to get directions from a real person who knows the area as well. Just to be safe.