They're experimenting with fake speed bumps in Philadelphia -- 3-D paintings on roadways that give drivers the misimpression that there's a raised speed bump in the road, when all it is is a painting.

Is that such a good idea?

It's been tested before and, sure enough, it does slow drivers down -- temporarily. Until they figure it out.

Now all you've done is undermine respect for authority, and conditioned drivers to not believe what they see. And, like the faux speed bumps, all you've gotten is an illusion of safety: drivers slowing down temporarily, until they realize the speed bumps were optical illusions.

Wouldn't it be better to simply enforce the law against speeding? Or teach young drivers to obey the rules of the road without having to be watched?

Or, in the alternative, put in real speed bumps?

Fact is, when society sets rules and laws, then ignores them, that encourages young people to ignore them as well. When one rule or sign is ignored, others tend to be ignored too.

That was tragically demonstrated over the weekend when 17-year-old Asia Leeshawn Ferguson, visting Six Flags Over Georgia with a church group from Columbia, S.C., was decapitated by the amusement park's "Batman the Ride" rollercoaster.

Authorities say Ferguson and another teen had climbed two six-foot fences to enter the restricted area through which the roller coaster zoomed. Police say there were warning signs.

In most such cases, there would be a quick lawsuit and, perhaps, an unwarranted payoff. But relatives of this young man have already said they don't blame the park. And we commend them for that.

Instead, if anything can be blamed, it's youthful indiscretion and a societal tendency to not heed, or perhaps to not believe, warning signs.

We don't need fake speed bumps. We need warnings you can believe.

And then we need to heed them.