Though radar signs can promote speed awareness everywhere they're used, one study done by the TTI (Texas Transportation Institute) actively compared them against other methods like police radar and rumble strips. One of the biggest points of interest in the study was that instead of just hard speed data, they also took into consideration things like ease of use and how long it took for the various methods of traffic control to be set up.
The measurable effects of the signs against things like the rumble strips and the radar drones designed to mimic police radar were clear. The signs dropped the average speed by 5.2 miles per hour compared to the 1.6 mph average drop for both the strips and the radar. When every mph counts in a vehicle/pedestrian accident, it's clear that the signs make the area safer than the other methods.
Another factor is the percentage of speeders mixed in with the traffic. The rumble strips showed the highest percentage of speeders that slowed was a 2.8% drop in speeding cars as they approached the construction area. The radar drones actually were the most ineffective, with the number of speeding cars approaching the zone actually going up by 10%. But the radar speed display signs dropped the number of speeding cars by 6.9%, and dramatically dropped the number of speeding trucks by 15.7%.
So overall traffic slowed, and the number of speeders was reduced far more than with police radar or rumble strips. But these data alone weren't what helped the signs really outshine the other methods. The signs and the radar drones were both fast and easy to set up, but the construction workers didn't feel the radar would help protect them while they were generally confident that the signs would make a notable difference.
The rumble strips, on the other hand, took about 40 minutes for a crew of three to install along the road, wasting time on a method that didn't have much of an impact on traffic. Workers felt that the rumble strips took too long, and worried about how easily they could be installed on 4-lane roads. Traffic would have to be completely halted for installation to be safe on some roads, taking even more time and manpower and causing congestion on the road.
Speed signs and other devices weren't the only things the TTI test took into account. They also tested things like different worker vest colors, and surveyed drivers to see if they noticed the difference, or found the workers more or less visible than before. Fluorescent orange roll-up signs rather than the typical signs were also tested, with about 15% of drivers saying they were more noticeable.
In this one day test of traffic calming methods, the speed display signs were clearly the most effective method of making construction and work zones safer. In some areas where a higher danger is perceived, the signs combined with other methods may offer even more protection. Contact TraffiCalm today about how work zones in your area can be made safer with speed display signs.
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