Time travel has become a sci-fi staple. Some characters have a machine or a gift that allows them to go from the present - whoosh! - to a point minutes or years in the past or future. Ever wonder, "what if they suddenly appeared where there was a building, or in the path of a speeding car?"

It is not just sci-fi characters (or writers) who confront this problem. All of our vehicles have this dangerous power and people fall victim to it every day. In books or movies, characters push some button or lever, or make a wish, and pass through a chunk of time unaware. Drivers just turn their minds elsewhere. The vehicle keeps going, keeps passing through time, and when the driver tunes back into the story (the journey), there's a speeding car or a building or a pedestrian right there.

Looking away is not the only cause of this trouble. Just because something is in front of our eyes doesn't mean we see it.

Take the new stoplight on Cedar Avenue, Highway 77, in Minneapolis. Recently, my wife and I were driving south on Cedar, commented that the light was new, and slowed because it was red. Not only was the light red, but a car coming northbound had stopped and was waiting to turn across our path. Another car traveling our same direction contained a motorist who was looking but not seeing. He laid on the horn, slowed down for fear this oncoming northbound car was going to "dart out in front of him" and continued blasting the horn until the car finally went - perhaps against the red light - and then he tromped the gas, drove past us and ran the light that we were still stopped at.

Clearly, he never saw it. Part of the reason for this is that it is new, unexpected. Yet there it was, of the same type, height and placement as any other traffic light. His eyes were facing it but his mind was on auto- pilot. He was traveling unaware, like characters in movies who leave 2009 and suddenly appear in 1943. It's dangerous to turn our eyes away from the road more than an instant, but we shouldn't turn our attention away from it, either.

Maybe the old highway-safety slogan "keep your eyes on the road" needs a companion: "keep your mind on the road."

Driving is like the children's game where you look at a drawing of, say, a farmyard, and have to locate the shoe, the spinning wheel, the iron, the hoe, the pitchfork . . . They're all there; your eyes are looking right at them. But it takes your mind a while to direct its focus all throughout the picture until the objects become recognizable. The driver on Cedar was proceeding directly down the middle of his lane. He saw the lines on the road. He saw the car sitting close in the oncoming lane. He may have looked briefly at and seen his horn button on the steering wheel before pressing it for a long time.

But he did not see the traffic light that was as much in his field of vision as any of these other objects. Driving with our hands at "10" and "2," thinking about what we're doing, studying the road ahead, with its pedestrians and bicyclists and motorcyclists and scooter riders, makes a difference. It keeps us alert time travelers. It prevents surprises. As the new season approaches, let's be wise characters at the wheel, or handlebars, and not arrive at danger unaware.