[Mpls] Red Light Cameras

[Chris Johnson]

John McClellan wrote:

> A few thoughts,
> 
> First off, yellow light duration is set according to
> MNDOT guidelines.

One would think so, anyway.  But in reality, many are not.  In the very same 
document Mr. McClellan quotes, it also states there should be an all-red 
clearance time of 1 to 5 seconds before traffic gets a green light.  I can 
name intersection after intersection where the all-red time is zero.  How many 
dozen such examples does it take to refute the idea that all traffic lights 
are adjusted to MNDoT guidelines?

> As some folks here have already pointed out, extending
> the yellow time longer will just give another car the
> opportunity to sneak through OR will increase the
> danger to the person that does actually yield to the
> yellow instead of blasting through.    

Those folks would be wrong in my opinion.  Yes, if many lights began 
exhibiting very long yellow light intervals, people might start running them 
in greater numbers.

However, the suggestions so far pointedly and erroneously avoid the real and 
reasonable suggestion made.  It's practically a straw man.  The point was 
increasing the yellow clearance interval ONLY at those intersections which 
have proven to be incursion accident prone and in which the yellow interval is 
either shorter than guidelines or on the short side of the range of suggested 
intervals.  That is what the series of articles in the Weekly Standard 
suggested, and is likewise what I was suggesting.

> Another option that has been used to decrease
> intersection crashes is to increase the "hold" time on
> the red - lengthen the duration of the red in all
> directions before changing the intersecting green
> light.  This gives the benefit of clearing the
> intersection while still making it clear that a person
> has run the red light.

Yes, that would help, although any increase in cycle time reduces the amount 
of traffic that can be moved through the intersection in a given interval. 
And yes, that's also true of longer yellows as well.

> I think it's also worth commenting that the purpose of
> a yellow light is not to convey "Oh, let me interupt
> my cell phone call to punch the gas so I don't get
> delayed by 30 seconds at a red".   It's also not to
> say "OHMYGOD! The lights going to change, jam the
> brakes!".     It's to communicate to the driver that
> the light will be changing soon, and if they can
> safely slow and stop to do so, but if they are too
> close to stop then they should procede through the
> light safely and clear the intersection.   The key
> thing here is the driver's decision about their speed
> and their ability to stop before the light.   There
> will always be people that are either unable or
> unwilling to make an intelligent/safe decision.    

I would argue that too many people pay so little attention to driving that 
they are incapable of making such an intelligent/safe decision.  But what's 
that got to do with proper use of red light cameras?

As I said before, I support the idea of red-light cameras IN THEORY.  I'm all 
in favor of giving red light and stop sign runners expensive tickets, several 
of them a day, if necessary.

But it's the devil in the details of implementation that bugs me.  I am unable 
to find not one single American instance where red-light camera usage was done 
correctly.  Instead of setting the yellow and red light clearance intervals 
correctly at accident prone intersections, and THEN placing red light cameras 
at them, cities like San Diego and Washington D.C. did otherwise.  They placed 
the cameras at intersections with high traffic volumes, often at the bottom of 
down grades, and ignored many of the safety problem intersections.  In surveys 
of the camera intersections, many were found to have sub-standard (shorter) 
yellow clearance times -- thus making it almost impossible to make "an 
intelligent/safe decision" because there wasn't enough time to react.

While paying lip service to safety, both the companies and governments have 
only focused on revenue.

That's my beef.

I will gladly support Minneapolis installing and using red light cameras if:

1. They provide the public a list of the accident rates at the top 500 
intersections in the city.

2. They provide the public with the light cycle timing information for the 
same 500 intersections.

3. They only install red light cameras at intersections selected from that 
same list of 500.

4. They produce a reasonable piece of legislation codifying the privacy and 
accuracy requirements which any vendor company must adhere under penalty of 
law, not just some contractual language.

5. Anyone receiving a ticket at an intersection where the timing can be shown 
to have been altered outside of accepted traffic engineering values can have 
it dismissed.


> Another valuable resource is this document that gives
> the stats on a red light camera test project here in
> the Metro back in 1998,
> http://www.dot.state.mn.us/trafficeng/reports/MIRSRPT98.pdf
>    Note some of the statistics, at 5th Ave & 9th St in
> Mpls, 56% of violators entered the intersection 1.0
> seconds after red, 35% after 1.5, and a frightening
> 18% after 3.5 seconds!!

Must be the same people who actually speed up to run the stop sign on my 
neighborhood corner.


Chris Johnson - Fulton