Traffic calming has previously been
shown to reduce instances of speed in the City. And now here's more poof:
This summer, the City installed a traffic calming island in the
intersection of Montrose and 10th Street in order to slow down motorists on Montrose Ave, which has a
speed limit of 25mph. This new concrete center-island median is bisected with a ladder-style crosswalk and has added signage to improve visibility. DPW conducted a "before" study to determine the number of speeders prior to its installation. After letting drivers adjust to the presence of the new island for a couple of months, we conducted an "after" study to compare the island's effect on driver behavior. Here are the
results:
- Speeders in excess of 25 mph decreased from 72.5% of all vehicles to 41.3% of all vehicles.
- Speeders in excess of 30 mph decreased from 47.7% of all vehicles to 14.1% of all vehicles.
- Speeders in excess of 35 mph decreased from 19.4% of all vehicles to 2.4% of all vehicles.
- Speeders in excess of 40 mph decreased from 4.7% of all vehicles to 0.3% of all vehicles.
The results, while not perfect, show that speeding drivers slow down dramatically when there is a large concrete island in the middle of the road; speeding drivers apparently prefer slowing down over crashing. Call it blunt, but nothing else reduces speed as much, or is more cost-effective than simply removing,
by design, the ability to speed.
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Before and After Study showing effect of traffic calming on Vehicle Speeds |