Effect of Photo Enforcement in Illinois Highway Work Zones
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   17 years
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Finally, something that shows the effectiveness of photo enforcement cameras and manned police sites in work zones. The entire report can be downloaded from
http://ict.illinois.edu/Publications/report%20files/FHWA-ICT...
The effects of an automated Speed Photo-radar Enforcement (SPE) system on the speed of vehicles in highway work zones were evaluated in this study. The SPE effects were also compared to other speed management treatments, including speed display trailers, police presence (with the patrol emergency lights on and off), and the combination of speed display trailer and police presence. Three datasets were collected in two work zones and the effects were studied at the location of the treatment and also at a location about 1.5 miles downstream in the work zone (spatial effects). The halo
effects (temporal effects) of police presence and SPE, after they left the work zone, were also analyzed. Results are presented separately for cars and trucks in free-flow and in the general traffic stream in the median and shoulder lanes.
SPE reduced the average speed of free flowing cars in the median lane by 6.3-7.9 mph and in the shoulder lane by 4.1-7.7 mph. The reductions brought down the average speeds near or below the posted speed limit of 55 mph. In addition, the SPE reduced the speeding by 40-51% in the median and by 7-57% in the shoulder lane for free flowing cars. Similarly, for free flowing trucks SPE reduced the average speed in the median lane by 3.4-6.9 mph and in the shoulder lane by 4.0-6.1 mph, to speeds below the posted speed limit of 55 mph. SPE also reduced the speeding free flow trucks by 10-53% in the median lane and by 0-56% in the shoulder lane. For the general traffic stream, SPE reduced average speeds by 5.1-8.0 mph in the median lane and by 4.3-7.7 mph in the shoulder lane. Likewise, trucks in the general traffic stream traveled 3.7-5.7 mph slower in the median and 3.9-6.4 mph slower in the shoulder lane. SPE lowered the average speed of the general traffic stream below the speed limit in all cases. SPE was as effective as the police patrol presence with the emergency lights off. In two of the three datasets, SPE had 2.0-3.8 mph spatial effects on free flowing cars and 1.1-1.9 mph on cars in the general traffic stream. However, on all three datasets SPE had 0.8-5.3 mph spatial effects on free flowing trucks and 0.9-3.2 mph on trucks in the general traffic stream. The reduction in the percentage of downstream speeding drivers varied from 0%-44%. Finally, halo effects were very limited and only observed for SPE on free-flowing heavy vehicles in one work zone and free flowing cars in the second work zone. Police presence did not have halo effects.
Thanks
The results are as expected. Cameras can serve a purpose. I presume the cameras are up and on only while road crews are working...
Tuckahoe Mike - Nuvi 3490LMT, Nuvi 260W, iPhone X, Mazda MX-5 Nav
Ban Them
There are lots of things that might be effective, but that doesn't mean we should do them. They can do anything with the numbers and the fact that they are out there measuring speed, might impact the study as well. If I had just seen a posted camera van and then later saw someone else measuring speed, I'd be suspicious of it. The most important numbers I saw in there were $375 and $1000 which are the amounts of money that motorists are being robbed of. It's just a big money grab and these things ought to be banned.
Dream On
They can post whatever their observers saw. What I see every time I ride on I-88 from US-59 east to US-83 is there are always some drivers going 80-90 mph, even in the ridiculously slow 45mph "construction zones".
The "construction Zones" have the Jersey barriers up and in other states, there is no speed reduction. All the posted 45 does is to make a wider differental between safely traveling vehicles and those that will go much too fast for conditions. These highways were designed for 65-70mph, unless congested. Trying to slow drivers down significantly below that causes more problems than it solves.
The report quotes a 55 mph work zone speed limit. What!! In Illinois I've never seen a work sone speed limit other than 45mph on the NE IL tollways. They must have been studying the rural system. I wouldn't put much faith in a student term paper like this.
Zumo 550 & Zumo 665 My alarm clock is sunshine on chrome.
But it didn't affect
If I had just seen a posted camera van and then later saw someone else measuring speed, I'd be suspicious of it.
But someone measuring speed didn't slow down drivers after they passed a police car or other devices. Drivers only stayed slow when a camera was used.
ɐ‾nsǝɹ Just one click away from the end of the Internet
Solution?
So, I suppose the solution is to do away with speed limits all together. At least that should give us something legitimate to complain about, huh?
Tuckahoe Mike - Nuvi 3490LMT, Nuvi 260W, iPhone X, Mazda MX-5 Nav