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I'm with you RJ. My biggest frustration with this city is the lack of synchronization of the traffic lights. I've always found it so puzzling since the city is indeed structured in a grid and shouldn't be that hard to sync up. It seems like no matter where I'm going or coming from the lights do not sync green.
I used to drive west on Ellison/McMahon (coming from Alameda) to get home everyday and would get stopped at one red light and after waiting literally 2 minutes I would get to the next light only for it to JUST turn red (sometimes with no cars going at the other light). And many times I travel east or west on Paseo and for the life of me cannot hit all the lights green no matter how fast or slow I go. Same with north/south on Coors.
I've wondered if they do it to get people to not speed?...but then, why doesn't going the speed limit or slightly below get them to sync up either? It's a complete waste of gas and horrible for the environment if you ask me.
I've always found it so puzzling since the city is indeed structured in a grid and shouldn't be that hard to sync up.
Quote:
David Mitchell, director of operations and maintenance for the county, says signal timing “turns out to be a very difficult balancing act. I found out you can’t just increase the ‘total cycle time’ of the intersection to give one leg more time, because what happens is another intersection down the line, such as Broadway, goes from a grade “E” to “F” for one of the arrow signals there. As a result of us having all these coordinated signals on the main roads, or synchronized lights as most people know them, if you want to change the cycle time on one intersection, you have to change them all.”
Determining if that could/should be done is Robert Baker, who’s in charge of signals and signage for the county. He says “depending on the time of day, the north and south through movements get anywhere from approximately 18 to 40 seconds of green time — about 40 in the a.m. peak, 21 during the day and 18 in the p.m. peak. The all-north and south movements run on detection, so if there’s more than a 2.5 second gap between vehicles, then the signal will turn green for Rio Bravo traffic.”
So that means right now Augusta gets the 18-second maximum green time each time she tries to get through the signal, and she has to wait for a gap in the Isleta traffic to get another shot at crossing Rio Bravo.
The problem with Albuquerque is the city does not put a high priority on traffic efficiency, despite what they may actually say. That is, they don’t want to spend the bucks to effectively utilize the capable system they already have.
From what I am aware of, the city already has most of the expensive signal interconnections existing in place. However they seem to lack a “real” traffic management center to efficiently operate these interconnected signals and have not spent the funds to do real signal timing analysis. Timing of traffic signals is quite labor intensive, and requires a lot of traffic counts. A rough rule of thumb is that it costs around $2,000 to $2,500 per traffic signal coordinated to collect the data, implement the timing programs and do followup tweaking. Any halfway decent traffic engineer can get rough signal coordination going, but it takes a lot of data to really do it right. And it’s far more complex than the lay public thinks. In some cases, with either very heavy traffic or very light traffic, it makes more sense NOT to implement signal coordination.
However the benefit/cost ratio for traffic signal coordination can be huge, much more so than other road improvement projects. I once implemented a coordination plan for about 50 or so signals in a city of around 135,000. When I calculated the benefit cost ratio to be over 18 in the first year of its operation, I was sure I made a mistake. So I recalculated, and found I did, it was actually 20! (A ratio of 5 would be great for a public works project) The values took into account gas savings for the citizens and a modest amount for their time. So while signal coordination isn’t as sexy or noticeable as a new Paseo Del Norte interchange, it’s probably a better use of funds.
It really comes down to Albuquerque not having the number of people they need to do the job right. In fact, they have only about a quarter of the staffing they need. The following are excerpts from “Albuquerque Area Regional Traffic Management Center, Concept of Operations”, September 23, 2011
“The COA has three staff members responsible for traffic signal and CCTV operations, in addition to their other traffic engineering duties. The current staffing level is insufficient for the existing workload. Based on Institute of Traffic Engineers (ITE) guidelines, staff is at approximately 25% of the desired level. Because the staff is so thin, no one is assigned directly to monitoring arterial traffic operations. The City is assessing an agreement to enable NMDOT to operate its arterial DMS. Traffic staff is available from 7:00 AM to 3:30 PM on normal work days.”
And this....
“6.4 City Of Albuquerque Traffic Signals
The City of Albuquerque Traffic Engineering group is responsible for traffic signals and traffic analysis within the City. The Traffic Signal group manages over 600 traffic signals, plus some 11 DMS and approximately 80 CCTV. Staff is located at the Pino Yard in north Albuquerque, and in a temporary trailer located on Wyoming. Staff located at the trailer is responsible for monitoring city cameras, managing traffic signal operations and signal timing, operating the DMS, and locating city utilities. The city has an extensive fiber network; about 75% of the signals are on fiber and the remainder is on twisted pair.
There are a total of five staff, three engineers, one utility spotter and one electrician who are mostly in the field working on intersection signals. ITE guidelines suggest that approximately 12 engineering staff would be sufficient to manage the traffic signals, communications network and DMS. Because of the staff shortage, they do not operate the City DMS, and are currently working on an agreement to allow NMDOT to operate them.”
A few lessons on Signal Progression - or coordination or "synchronization" (which it is not).
Most people think that signal progression is easy. It is not. In fact, oin many streets it is impossible.
A few facts:
- One-way streets are much easier to progress than two-way streets.
- Setting perfect offset times for one direction usually produces awful times in the opposite direction.
- Often signals are progressed for only the direction with the heaviest traffic flow.
- For good two-way progression, the engineer does not have much of a choice of progression speeds.
- Progression speeds are usually dictated by the locations of traffic signals along the street.
- Short signal spacings, varying signal spacings, and changing speed limits make progression harder.
- Progression at speeds other than the speed the traffic is moving at will not work.
- Different progression plans are needed for different times of day.
- Speed limits must not be set lower than actual traffic speed. Progression won't work in such cases.
- Left turn signals on the cross street usually make progression extremely difficult.
- Usually streets near a progressed street can not also be progressed, unless blocks are unusually large.
- Traffic actuation of individual movements usually hinders progression. Fixed time signals work better.
- Unusual sequences (e.g. lead-lag left turns) can allow progression where it otherwise won't work.
- Flashing yellow arrows make the lead-lag sequence safe for permissive turns.
Having been a frequent road warrior myself, I can say that Albuquerque beats both Colorado Springs and Tucson for light timing hands down. CS in particular is an abomination (ever waited at a light for 3 minutes solid?).
W H A T ?
I did an enormous amount of traffic research and decided to move to Colorado Springs in part because of the great traffic flow. I commute eight miles and on average stop at 3-5 intersections. No disrespect Zoidberg, I just don't think you've spent much time in CS. When I lived on the West Coast, you waited for 3 minutes or more regularly if you went anywhere in rush hour. CS streets are set up to encourage drivers not to left turn onto major roads. It slows everyone else down, and the lights reflect that.
I did an enormous amount of traffic research and decided to move to Colorado Springs in part because of the great traffic flow. I commute eight miles and on average stop at 3-5 intersections. No disrespect Zoidberg, I just don't think you've spent much time in CS. When I lived on the West Coast, you waited for 3 minutes or more regularly if you went anywhere in rush hour. CS streets are set up to encourage drivers not to left turn onto major roads. It slows everyone else down, and the lights reflect that.
I have traveled extensively throughout this great land of ours, including California. California's congestion is legendary and not my first choice but it's not on account of horrible light timing. Colorado Springs has snow to complicate matters but it's bad traffic engineering that ranks it behind all but the densest west coast cities for overall driving.
To this day, I have not seen anywhere near as bad for light timing as Colorado Springs. The main factor is just how long red lights stay red.
Places with heavy traffic are going to be slow-going regardless. What sets Colorado Springs above and beyond the rest for awful traffic planning is how long it takes to get across town when there is no traffic or light traffic.
Your commute may not involve a particularly bad stretch of Colorado Springs, but it doesn't mean there aren't pretty awful stretches.
To bring this back to the topic at hand, Albuquerque's quite good for light timing; there's always room for improvement, but I've seen how badly it can be done in certain other places.
I have traveled extensively throughout this great land of ours, including California. California's congestion is legendary and not my first choice but it's not on account of horrible light timing. Colorado Springs has snow to complicate matters but it's bad traffic engineering that ranks it behind all but the densest west coast cities for overall driving.
To this day, I have not seen anywhere near as bad for light timing as Colorado Springs. The main factor is just how long red lights stay red.
If any signals are progressed, the cycle length cannot be arbitrarily chosen. It is dictated by the pattern needed for progression to work.
Quote:
Originally Posted by Zoidberg
Places with heavy traffic are going to be slow-going regardless. What sets Colorado Springs above and beyond the rest for awful traffic planning is how long it takes to get across town when there is no traffic or light traffic.
If you come up to a signal on a side street with actuated side street control, you may have to wait the entire cycle length before you get a green. And if you drive beyond the stop line, you will have to wait until another car comes up behind you before the signal changes. You drove off the detector.
If any signals are progressed, the cycle length cannot be arbitrarily chosen. It is dictated by the pattern needed for progression to work.
Cop: "How fast do you think you were going?"
Troubleshooter: "The traffic rate cannot be arbitrarily chosen. It is dictated by the pattern needed for progression to work."
Cop: "I'm writing you a speeding ticket for $500. You have 30 days to pay the fine or contest it in court."
Quote:
If you come up to a signal on a side street with actuated side street control, you may have to wait the entire cycle length before you get a green. And if you drive beyond the stop line, you will have to wait until another car comes up behind you before the signal changes. You drove off the detector.
Someone's driven off the detector, all right.
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