Speed Bump or Speed Hump?

Before choosing a traffic-calming device, it’s best to first determine the main problem that needs to be addressed, as well as all the variables involved.

Depending on the location, whether it be in a parking lot or on a residential road, some solutions are more appropriate than others. Without looking at the whole picture, you might choose a less suitable option, and you’ll find yourself right back at the same location working on what you’ve already done.  That can be costly, and chances are your customer will not be happy.

Here’s an example of how the big picture can affect the final outcome.  Let’s say you’re installing a traffic calming system at a shopping center.  And the owner wants to slow traffic in front of every storefront to make it safer for pedestrians to cross.  You might think ‘the slower the better’ in this kind of situation.  Since our speed bumps are designed to slow traffic to 2 – 5 mph, this might sound like the perfect option.

But, let’s consider that one of those storefronts is at the entrance of the shopping center, and just off a major highway.  At 2.25″ high, the speed bump is pretty aggressive.  Vehicles normally stop, or almost stop before rolling over each speed bump location.  Under normal conditions, that might not be so bad.  But let’s consider the effects of this during a busy rush.

A vehicle comes off the highway, and has to hastily slow or almost stop to drive over the bump.  What happens to the car coming in behind that one?  And the one behind that?  If the line of traffic is slowed too abruptly right inside the entrance of the shopping center, there’s a good chance that it will become congested and back traffic up onto the highway.  The drivers are unhappy, the pedestrians are crossing between vehicles, and the owner starts complaining.  Not to mention there’s now a backup on the main road, and that’s unsafe for the drivers trying to pass by.

Now let’s consider a speed hump instead.  Because this is less aggressive, vehicles are more apt to slow, but not stop before rolling over them.  A vehicle entering from the highway will need to slow, but they can keep moving without damage to their car.  Now, traffic will keep flowing smoothly, but they will be forced to slow, making pedestrian crossing much safer.  Plus, traffic is still moving so there’s no congestion on the highway.  Now you’ve got happy drivers, happy pedestrians, and a happy owner.

It’s probably okay to install bumps at the rest of the storefronts, depending on the layout of the plaza.  Once vehicles enter through that main entrance, there’s a good chance they’re going to disperse throughout the parking lot, and traffic won’t be as heavy in front of the other stores as it is in this entrance location.  Just be sure to look at the other variables to be sure that what you’re installing to make the lot safer isn’t causing a hazard somewhere else.