Half of SF’s Traffic Signals to Get Transit Priority Within Two Years

Photo: ##http://www.flickr.com/photos/gazeronly/6721389023/##torbakhopper/Flickr##

Two years from now, Muni buses will have traffic signal priority at 600 intersections throughout the city, SFMTA Transit Effectiveness Project (TEP) Manager Julie Kirschbaum told the agency’s board of directors today.

The signals will speed buses along all of Muni’s priority “rapid” route network, which encompasses half of San Francisco’s roughly 1,200 signalized intersections, she said.

Transit-priority traffic signals would substantially speed up Muni trips by “allow[ing] us to extend greens and reduce the amount of time buses spend sitting at signals,” said Kirschbaum in an update on the TEP [PDF] presented to the board.

The signals, which would use GPS to hold green lights for buses and trains as they approach an intersection, will be installed using $20.3 million from the Prop B street improvements bond measure approved by voters last November. “It really is a substantial investment,” said Kirschbaum.

Although staff is currently performing environmental review and public outreach on physical street improvements recommended in the TEP, other improvements are moving ahead, like signal priority and system-wide all-door boarding, which is expected to begin on July 1.

When the rest of the TEP is implemented by 2017, said Kirschbaum, it will add other street improvements to facilitate signal priority, including colored bus-only lanes, right-turn lanes for other vehicles, and bus stops moved to the far side of intersections.

Some intersections already have transit-priority signals, but staff said they use outdated technology, and many have been poorly maintained. The new signals will also replace stop signs on some routes.

  • mikesonn

    Does this include turning on the ones already installed along Embarcadero & Third? Or they have been “poorly maintained” and need to be replaced?

  • San Francisco has just 1200 intersections? That sounds waaaaaaaay low…

  • Anonymous

    Nice to see some actual progress in implementing the TEP.

    The map in the presentation has the K/M line from West Portal to 19th Ave marked as an ‘ongoing Muni project’. Does anyone know what this is? West Portal Ave could certainly use transit-only lanes.

  • Anonymous

    Maybe it refers to “intersections that Muni buses cross which have traffic lights”?  That would make more sense in the context of the article, but I’m just making a guess here.

  • Aaron Bialick

    The direct quote from Kirschbaum: “Just to give you a scale, we only have about 1,200 intersections citywide, so it really is a substantial investment.”

  • Anonymous

    That must mean intersections that Muni goes through. I would put the total number of intersections closer to 10,000 than 1,200.

  • Aaron Bialick

    I did a little more digging and found that it’s 1,200 signalized intersections. My sincere apologies, folks. I made the appropriate changes in the article.

  • ubringliten

    2 years from now is such a loooooooooooooooooooooong time.

  • Davistrain

    I wonder how long it will be before some “hacker” figures out how to “fool” a traffic signal controller into thinking his car is a Muni vehicle.

  • Mario Tanev

    I’ve heard this reference to signals that haven’t been turned on along the T line before. Do you have any pointers to where that information is coming from? I am wondering if it’s just a myth, or something that Streetsblog should perhaps look into? As far as I know, signals have been turned on Third Street. At 4th and King there is contention between the N and the T, and perhaps the timing there is not correct.

  • mikesonn

    4th/King is something I deal with every day. Those lights are on the same rotation with a N/T there or not. I don’t believe there is any signal priority because the SFMTA feels all the traffic needs to move at regular intervals to prevent back ups. Though, this is only a guess as to their reasoning.

    And as for where I got the info about EMB, sadly I do not recall.

  • Richard Mlynarik

    Give us more money and we’ll do what we said we’d have done two decades ago.

    This time for sure.


  • The Greasybear

    4th and King signals cannot be optimized for transit because it would violate California LOS (Level of Service) requirements, which is to say, it would make private automobiles wait “too long” for trains to pass. 

  • John Domblides

    Moving bus stops to the far side of intersections works very well, however bus priority at signals is problematic at best. Any advantage given by bus priority on one approach often causes more delay, congestion and pollution on the other affeced approaches. Without any doubt the greatest reduction in bus journey times and improvements in bus punctuallity can be gained by reducing the time waiting at stops..

  • Anonymous

    Well, SF have decided to abandon LOS as a metric for future EIRs in favor of a metric more favorable to transit. So hopefully the EIR for the TEP will include analysis showing that activating these signals will not cause cause cars to wait “too long”.

  • icarus12

    Agreed.  I have never understood why the trains on West Portal should have to stop or slow behind automobiles when there’s a another full lane for automobile travel to the right of the train tracks, plus parking.  Also, the train signaling at West Portal and Vicente coming out of the tunnel is currently controlled by four stop signs! Frightening, to say the least.  Does Streetsblog or any reader here know if SFMTA can win priority for sending trains in and out of the tunnel down West Portal Avenue and just make the car drivers wait.  Seems only fair.

  • mikesonn

    LOS assumes all vehicles = same number of people. This is obviously not true. So when a private auto is equated to a transit vehicle (on passenger count alone), the metric falls flat on its face.

  • Tell me more about the benefits of locating bus stops on the far side of intersections. I was under the impression that this placement is only to the benefit of those driving private cars (so they are not stuck behind a bus boarding passengers when they are trying to turn right). For those traveling by bus, it seems to only slow things down, because the bus will often have to stop twice – once for the signal (where it can’t board/alight passengers) and again after the signal at the official bus stop.

  • Aaron Bialick

    @twinpeaks_sf:disqus With signal priority, the buses shouldn’t have to stop at the light. But Kirschbaum has said said the concern you raise does apply to stop signs, where the SFMTA wants to move bus stops to the near side of the intersection instead.

  • mikesonn

    Signals with no bus priority, the problem can be had with near or far side stops. I’ve been on plenty of buses (more notably the F-line), that stop near side, load, then just miss the green so they have to sit through a whole light cycle. It goes both ways.

  • Very true @mikesonn:disqus. I think that’s how it goes the majority of the time on Market too.

    Aaron: Maybe with transit signal priority we can have it both ways. In theory, the bus doesn’t have to wait at the intersection and can proceed straight across the intersection to the bus stop. Car drivers benefit too because they don’t have to wait behind the bus to complete their turn movement. Win-win. Let’s hope Muni pulls this off.

  • Nico

    How do I get this GPS on my bike?

  • Mario

    Mark, another problem with near side stops is that when drivers have the light they block the bus stop. In the worst case the bus may have to stop 3 times per intersection: waiting for the obstacles to clear, boarding, waiting for a green light. That problem does not exist at fast side stops except in complete gridlock.

    As for there being more stopping required with far side stops, it’s not really true, since in the absence of signal priority, the bus is not in sync with the light, so it’s equally likely for the bus to board at the near side and then stop at a red light as it is for it to stop at a red light and then board at the far side.

    With signal priority you get the added advantage of time to switch the signal once you see a bus a block away. If the stop is immediately before the intersection, you have to predict boarding time which is harder.

  • Good insights, Mario. I knew there was more to the story of nearside versus farside bus stops. Now I can stop getting mad whenever I see a farside stop – they’re not so bad after all and are seemingly better with transit signal priority.

    I guess it’s just frustrating when you’re wanting to get off the bus and have to wait until it crosses the street, even if it’s not inefficient.

  • Mario Tanev


    Perhaps drivers should be encouraged to let passengers off if the bus is stopped at a red light (some do anyway already). They would have to use their judgment however as for whether it is safe and whether the red light is going to last a while.

  • So you’re telling that instead of Muni drivers bringing buses to a stop at a green light with 5 seconds and sitting there, they’ll be doing that for 15 seconds instead?

  • Sprague

    As I recall the impressive Muni publications that touted the benefits of the T-Third line, from the late 1990s or early 2000s, signal priority for light rail vehicles was one of the selling points.  The T-Third was going to be faster than the bus line it was replacing.  Certainly by any measure, the amount of time it takes the T-Third to travel through the intersection at 4th and King is pathetic.  I only ride this a few times a month, but from my experience a good three minutes is about average for a Muni LRV to make it through this intersection.  Maybe LOS is the reason for this incredible inefficiency or is it Muni incompetence/improperly tuned transit signals?  Something sure ain’t right when it’s quicker to get off the N or the T at the ballpark and then hoof it to the Caltrain station.  As mikesonn points out, LOS is giving high occupancy Muni vehicles a worse level of service than their automobile counterparts.  Perhaps change is coming since a transit rider is now at the helm of the MTA.

  • Somebody

    Yeah,.and LA has only 4,385 intersections which are signalized. Compare to NYC where they have a HUGE number of traffic signal intersections. Get ready for this number. There are 12,460 INTERSECTIONS WITH TRAFFIC LIGHTS IN NYC!!


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