Synchronized Traffic Signals

[patric]

The city council last week passed Councilor Bill Christiansen's Traffic
Signal Synchronization Task Force, following a recommendation in the
city's new Comprehensive Plan.

With any luck, the first business at hand should be lengthening the
yellow-light interval to reduce crashes, and not shortening it to
increase revenue.

http://www.thenewspaper.com/rlc/docs/armey/finalreport.pdf

[patric]

It could be just coincidence...

""We need to continue to focus our efforts, leverage resources and partner in the way we spend our dollars investing in cutting edge strategies that enhance community policing, suppress gang violence, and support critical technology such as CompStat, cameras in cars and electronic ticketing."

MAYOR KATHY TAYLOR
FISCAL YEAR 2009 BUDGET MESSAGE
TO TULSA CITY COUNCIL

[nathanm]

I believe the reference to electronic ticketing was regarding the handheld computer thingies they now use to write the tickets.

I see enough red light running that I wouldn't be able to muster a bunch of outrage unless they further reduced yellow light times. Before doing that, I'd rather them increase the all-red period (there are several lights outside of downtown that have a zero all-red period) and have correct yellow lengths.

[patric]

I believe the reference to electronic ticketing was regarding the handheld computer thingies they now use to write the tickets.

I see enough red light running that I wouldn't be able to muster a bunch of outrage unless they further reduced yellow light times. Before doing that, I'd rather them increase the all-red period (there are several lights outside of downtown that have a zero all-red period) and have correct yellow lengths.

I think the gist of the article was that intersections that had 5-second yellow intervals were shortened to 3-second yellow intervals, and the difference was made up with a 2-second all-red interval, which then resulted in an increase of red-light running.

Also, if memory serves me, at least one councilor wanted to jump on the red-light camera bandwagon, but that was shot down because of all the publicity about their abuses.
   

[patric]

Christiansen is proposing using $165,000 for two new engineers.  Public works would move the money from other areas, but still needs the mayor’s approval.

“We’re asking the mayor to make an exception to the hiring freeze for these two positions,” says Christiansen.

http://www.fox23.com/news/local/story/Traffic-Light-Plan-Accelerated/EIK1_Mc8h06OrNrya1I-pw.cspx

[dbacks fan]

Just a couple of suggestions from what I have observed in the Phoenix Metro area that work well to cut down on accidents with regard to traffic signals and major intersections. First is a 5 second red in all directions. It does cut down on people being hit by red light runners, it's suprising how effective 2 seconds is. The other is lagging left turns in conjunction with the five second all red. Instead of leading left, the lagging left tends to keep left turn drivers in place, and allowing them a three second advantage that is incorporated into the five second all red. Is it perfect? No. But it does reduce left turn accidents.

[Hoss]

Just a couple of suggestions from what I have observed in the Phoenix Metro area that work well to cut down on accidents with regard to traffic signals and major intersections. First is a 5 second red in all directions. It does cut down on people being hit by red light runners, it's suprising how effective 2 seconds is. The other is lagging left turns in conjunction with the five second all red. Instead of leading left, the lagging left tends to keep left turn drivers in place, and allowing them a three second advantage that is incorporated into the five second all red. Is it perfect? No. But it does reduce left turn accidents.

I know Houston uses (or at least did in the early 90s) the lagging left.  Took me about a month to get used to it.  Another month when I moved back..

[YoungTulsan]

This is badly needed and I am glad to hear.

[RecycleMichael]

I was kind of surprised it takes two engineers an entire year to do this job.

[Red Arrow]

I was kind of surprised it takes two engineers an entire year to do this job.

There are a lot of intersections to synchronize and on two way streets, the synchronization needs to be changed for the change in rush hour direction.   How many of the traffic lights will need hardware to link them together?  Two engineers and a year doesn't surprise me.

[Conan71]

If we are going to spend money on the engineers, I'd like to see them tackle the problem of winding up in red light hell on stretches of road like Yale from 21st to 71st.  It's especially wasteful in terms of fuel and emissions for vehicles to have to stop and accelerate at every light or nearly every light along that stretch.  I don't expect you would get a straight shot, but getting stopped at every single light is frustrating as hell and certainly does little to help on ozone alert days.

[YoungTulsan]

I was kind of surprised it takes two engineers an entire year to do this job.

If anything, it is the construction that is making the problem worse.  Major shifts in traffic flow are happening every month due to different combinations of thoroughfares opening/closing/losing lanes/etc.

I'm pretty sure I saw on a news story once in the last couple of years that we have one billybob in overalls looking guy in charge of setting the timings on every single light in the city of Tulsa.

Off of the City of Tulsa's website:

Streets and Expressways
Expressways - 465 Lane Miles
Arterial Streets - 1,249 Lane Miles
Residential Streets - 3,040 Lane Miles
Central Business District - 93 Lane Miles
Signalized Intersections - 491
(includes school crossings)

I could see having three engineers only being a temporary need until the overall flow is optimized, then dropping down to two after the 6 months or year it takes to catch things up.  We're pretty much going to be in widespread construction zones for the foreseeable future though.