Denver Must Prove Red-Light Cameras Improve Safety

An anonymous reader writes "An audit of accidents at Denver intersections where red light cameras were installed versus increasing the length of the yellow light shows little difference in the results. In a case of putting the public ahead of the corporation, the Denver auditor is recommending canceling the red light camera program unless the city can prove a public-safety benefit." I hope that private citizens offering analysis or recommendations are treated fairly.

Comments

I Seem To Recall

[sycodon]

...reading some years back that the Red Light camera companies had specific language in the contracts that restricted the length of yellow lights.

A cynical person might think they wanted people running red lights. But I'm not...oh, fuck it. I am cynical.

Re:I Seem To Recall

[digitalaudiorock]

As I recall, cities were in fact called out for shortening yellow lights for profit, and risking lives in the process. A quick Google search found this: http://blog.motorists.org/6-cities-that-were-caught-shortening-yellow-light-times-for-profit/

Re:I Seem To Recall

[bjdevil66]

Cities ABSOLUTELY cheat on yellow light timing - and they always will be because after they sign the contracts, they realize just how much money they HAVE to bring in just to pay the minimum monthly fees to the camera companies.

Case in point: In Paradise Valley, Arizona, they were caught red-handed by anti-camera activists intentionally shortening yellow lights going less than four seconds, which was a threshold they were never supposed to go under. The city claimed they weren't doing it, until this youtube video proved they were cheating at photo radar intersections.

After being caught red-handed, the city quietly and quickly - the very next day, in fact - changed the timing to match that minimum threshold.

In downtown Chandler, AZ, there was another well-known intersection with cameras with a shorter yellow time than the others, and it led to a majority of ALL of its camera "revenue".

Bottom line: There are a ton of revenue-desperate city councils out there full of dopes who aren't clever enough to see what the snake oil salesmen from camera companies are selling: "sin tax safety" AND revenue to boot, with a huge gotchas attached. It's going to take years to flush the system of these safety-neutral, revenue positive cameras.

BTW - Everyone should take notice that Los Angeles hasn't burned to the ground after turning off their cameras. It's safe to say that if LA can live without cameras, Denver (and any other major city in the United States) would probably avoid their own "carmageddon" as well...

Re:Are yellows in Denver really short?

[Anonymous Coward]

In many states drivers are taught to enter the intersection to take a left turn, and it's legal.

The MUTCD and ITE

[Joe_Dragon]

specifies that the duration of the yellow change interval should be between 3 and 6 seconds. And people have won court cases over red light tickets over the yellow time being too short.

http://www.ite.org/decade/pubs/IR-117-E.pdf

http://www.ite.org/safety/issuebriefs/Traffic%20Signals%20Issue%20Brief.pdf

http://www.ite.org/annualmeeting/compendium10/pdf/AB10H2601.pdf

Re:The MUTCD and ITE

[Anonymous Coward]

Also worth reading this - Oregon DOT Recommendations: http://www.oregon.gov/ODOT/HWY/TRAFFIC-ROADWAY/docs/pdf/ODOT_yellow_red_clear_policy_A1.pdf?ga=t

The 3 to 6 recommendation is based on some general assumptions and characteristics. It's still a mathematical equation. Also, here's a few c/p from the parent's references that are relevant (including the statement that yellow duration is commonly limited by control manufacturers and the shortfall is made up during a red phase):

The calculation requires values for perception/reaction time of the driver, deceleration rate for stopping vehicle, vehicle speed, approach grade (uphill, downhill), intersection width and design vehicle length. The standard value used for the perception and reaction time of drivers approaching a signalized intersection is 1.0 sec.

The Highway Design Handbook for Older Drivers and Pedestrians concludes that the 1.0-sec. reaction time is appropriate for both older and younger drivers, but that the use of a 1.5-sec. reaction time “is well justified when engineering judgment determines a special need to take older drivers’ diminished capabilities into account.”

The MUTCD (Manual of Uniform Traffic Control Devices) indicates that the yellow change interval should be set within the range of 3 to 6 sec. and many signal controller units will not permit settings outside of this range. If the phase change interval needs to be near the top of this range or beyond, the additional time is sometimes provided as part of a red clearance
interval.

Re:Are yellows in Denver really short?

[Attila Dimedici]

I have seen several studies showing a very distinct link between length of the yellow and safety. This study shows that increasing the length of the yellow decreases red light violations and this article references several studies that show that this effect does not diminsh with time. So, your gut is wrong on this one (although I understand why you would suspect that to be the case).

Re:Are yellows in Denver really short?

[Anonymous Coward]

"Oh no, the light is now red, there is intersecting traffic"

no cross traffic should enter the intersection until the way is clear.

Green != Go

Green = precede if clear

Re:Changed my mind

[Misch]

Was it Washington, DC?

Source

The [Washington] Post obtained a D.C. database generated from accident reports filed by police. The data covered the entire city, including the 37 intersections where cameras were installed in 1999 and 2000.

The analysis shows that the number of crashes at locations with cameras more than doubled, from 365 collisions in 1998 to 755 [in 2004]. Injury and fatal crashes climbed 81 percent, from 144 such wrecks to 262. Broadside crashes, also known as right-angle or T-bone collisions, rose 30 percent, from 81 to 106 during that time frame.
.
.
.
The results were similar or worse than figures at intersections that have traffic signals but no cameras. The number of overall crashes at those 1,520 locations increased 64 percent; injury and fatal crashes rose 54 percent; and broadside collisions rose 17 percent.

Overall, total crashes in the city rose 61 percent, from 11,333 in 1998 to 18,250 last year.

Re:Are yellows in Denver really short?

[Anonymous Coward]

It's also legal in Canada, or at least Ontario. The OP is a moron. You may always enter the intersection to perform a manoeuvre you have a green light for (in fact, the HTA says you can receive a ticket for NOT doing so). Once you are fully in the intersection, if you light turns red because you cannot complete the manoeuvre you are permitted (and required), by the HTA to complete the manoeuvre on red.

Yes, you must wait until the intersection is clear, that is also in the HTA, however, that is much more discretionary than the other directions, since the driver may start their left turn and realize the intersection is not clear before they complete their turn due to a blocked view or a car speeding up, at which point the driver is required to yield the right of way.

Furthermore, while it is horribly annoying when people overstep this and try to squeeze three cars though, it present absolutely no collision risk because the left turn is complete either during the time when the whole intersection is red (yes, the entire intersection is supposed to be red for a moment before the other traffic is allowed to move) or as the other light turns green (in which case they are stopped and notice you in their path so they wait to proceed). The only possible time I can see it being a problem is when a driver decides to speed at a stale red, not paying attention to the intersection, in the hope that the intersection will be clear and the light will magically turn green. That sort of driver was planning to run the red, anyways.

I *have* driven in an area where left turns on red are "illegal" (Philadelphia) and they aren't really illegal as far as I can tell. Instead, the left turn lights turn RED after they give you an opportunity to do a protected left turn. Notice that in the first paragraph I mention the driver must have a green light when they enter...

Re:Are yellows in Denver really short?

[colinnwn]

In most states, the person in the intersection (e.g. you), has the right away over people entering the intersection. Since in some states it is perfectly legal to enter the intersection on yellow, the people proceeding straight in front of your intended route have the right of way. This is of course ignoring how some people enter on yellow when they were perfectly capable of stopping safely. Once traffic finally stops, no one should be entering the intersection from crossing traffic until you are clear of the intersection. If they do, they are violating traffic law just as much as someone running a red light.

There should never be backing up in an intersection unless you think it is the only way to prevent a wreck, or reduce the severity of one. And even then, you better think twice, quickly.

Re:Are yellows in Denver really short?

[MobyDisk]

At this point you can either do a really dangerous left turn, or remain blocking the traffic, or try to back up (assuming people havent filled in behind you.

I've driven in a dozen states, all on the east coast of the US. In those states, this is not only permitted, it is the correct thing to do. It is taught that way in driver's education and a traffic cop will direct you to do this as well. When the light turns red, the driver in the intersection completes the left turn. It is not dangerous because there are a few seconds where the light remains red specifically as a time to clear the intersection. The only problem I've ever seen is when bad drivers either stay in the intersection and block it, or back-up - both of which are illegal.

Re:Are yellows in Denver really short?

[alexo]

I'd actually want to see a very clear causal link between longer yellows and safety increases, because my gut tells me longer yellows would make people ignore them even more.

For the Google-challenged:
http://www.thenewspaper.com/news/02/243.asp
http://www.thenewspaper.com/news/28/2887.asp

You can find more.

Re:Changed my mind

[Ichijo]

However, I changed my mind once a I listened to a local police chief explain that in his city traffic accidents had actually risen at the intersections where the cameras were in use.

This is not unusual. The Federal Highway Administration found that red-light cameras increase rear-end collisions but reduce more severe right-angle collisions, saving $50,000 in collisions per intersection per year in medical and repair costs.