Contractors who install speed bumps and speed humps might have to take up pavement marking if they want to keep that part of their business. Thatâ€™s because a new effort being tested in Philadelphia (after being tested semi-successfully in Phoenix two years ago) relies on pavement markings to slow drivers down. The new markings are designed to look like 3-D pyramids sitting in the middle of the road. To approaching drivers the "pyramids" are perplexing and cause drivers to slow down -- at least for a while. In addition to initial effectiveness, cities like the cost -- reportedly $60-$80 for the markings vs. as much as $1500 per speed bump. But maybe we should put the brakes on switching from speed bumps so quickly. The early research shows that while effective initially, the effect of the "pyramids" is short-lived. Drivers who take the road regularly revert to their former level of speed as soon as they realize the "pyramids" are just an optical illusion. Speed bumps, on the other hand, are effective as long as they're there, and as much as many drivers don't like driving over over them, they do their job.