Comments on: Valencia Signals Re-timed to Improve Traffic Flow and Safety

By: Jesse

Jesse — Tue, 07 Apr 2009 16:51:21 +0000

Reading through the comments it looks like some people missed the key point that the re-timed lights are intended to make car travel *faster*, not slower. The reason for the paradox: during times of heavy (car) traffic, average car speed is slower, and by matching the “green wave” to that slower speed, cars can avoid wasting time sitting stopped at lights. Yes, it slows things down a little during times of light traffic, when cars could successfully ride a 25mph green wave the whole way down, but hopefully the gains during congestion should be enough to make it worth it for cars.

As a bike commuter, I agree that 13mph is a little slower than I like for my morning northbound commute. But now that I know the lights are re-timed, I won’t have to race down Valencia to keep up with the wave, and that’s fine by me. I used to make it from 22nd to 16th without hitting a light, but this morning I made it all the way to 14th.

I think they re-timed some other streets recently too. Dolores at 23rd had previously been de-synched, apparently to keep cars from racing through after coming down the hill from 24th, but they seem to have re-synched it yesterday. And while I don’t know for certain after only one day, 14th st seems to have had better light timing as well.

By: C

Sat, 28 Mar 2009 06:07:06 +0000

I either ride or drive Valencia every day. I appreciate bicycle timing (though I agree with Greg about it being too slow even for bikes going north.) But I fail to see how slowing cars down to 13 mph, increasing the time that they are on the road and forcing them to use a lower gear, reduces gas consumption and carbon emissions. The longer it takes cars to get where they are going, the more cars are on the road. Slowing drivers to a frustratingly slow 13 mph is only going to make them irritated and impatient, which likely makes them more dangerous. If you’re going to time Valencia for bikes, perhaps Guerrero should be timed to commute direction for cars (and parking in the left lane prohibited.)

By: murphstahoe

murphstahoe — Mon, 09 Mar 2009 19:47:35 +0000

Hmm… I used to be able to catch a green at 17th and have green all the way to 14th. Now, they’re a little too slow for my taste but whatever.

By: jdub

jdub — Tue, 03 Mar 2009 16:43:17 +0000

Does this action indicate a new willingness at MTA to experiment with the street realm? If so, it marks a change that is most welcome and should be encouraged. This presumably was not studied endlessly, they just went out there and did it. Signage would have been nice so that drivers would know about how they might use the signals to their advantage, but this is a great step in the right direction.

Should there be a 20mph speed limit on all SF streets? What about retiming Franklin or Fell for 20 mph as an experiment?

By: Matthew Roth

Matthew Roth — Tue, 03 Mar 2009 02:14:39 +0000

I really enjoyed riding it today. Taking a leisurely pace from Cesar Chavez to Market, the downhill portion was almost perfect, a little bit slow. I’d catch up to the light and have 1-3 seconds before it would change. On the uphill back, the green wave pulled ahead of me by a few seconds, though I never got dropped. Again, leisurely pace–I’m sure some fixie kids would still find it too slow.

I also noticed that motor traffic was moving quite well, though drivers weren’t racing past me to get to a red light and wait. The trip out was at 3 pm, the return at 5 pm. So evening rush hour was not negatively impacted. It will be interesting to see what the engineers at MTA have to say about it.

thanks to them for giving this a try.

By: greg

greg — Tue, 03 Mar 2009 02:00:34 +0000

Looks like speed limits should top out at 20mph.

By: MichaelSF

MichaelSF — Mon, 02 Mar 2009 23:21:07 +0000

Nice job, Streetsblog, for pushing the idea! This is why we’re so happy to have you in town!

By: jass

jass — Mon, 02 Mar 2009 22:10:58 +0000

That’s exactly what needed, signage.

“Signals timed for 15mph speeds’

By: Greg Riessen

Greg Riessen — Mon, 02 Mar 2009 21:35:47 +0000

The new timing plan enables a green wave of about 13 mph in both directions. For cyclists, this works well because most casual riders want to travel around that speed. It is also an appropriate speed for cars given the amount of pedestrians, double-parked trucks, etc. Best of all, the current signal timing prevents cars and bikes from speeding through the yellow/red light, which greatly improves safety for pedestrians. The new plan is a vast improvement and the MTA should be commended.

However, in the morning on the way to work downtown, coming down the hill from 21st Street, there are many commuter cyclists that want to travel at the 18-22 mph range. This new timing plan stops them at every light. [Granted, this is better than the old plan: in order to ride the AM northbound green wave, a bike had to speed at 25 mph, zooming passed cars on the right and usually running the signals at 16th and 14th, and arriving at work in a sweat.]

Perhaps the timing could change in the AM to benefit faster northbound commuter cyclists, and the rest of the time maintain the current, casual 13 mph progression. A different plan is less necessary in the PM because of the uphill grade, and bike traffic is not concentrated in one direction. Given the wide variety in cyclist speeds and abilities, the MTA could optimize different signalized corridors for different users at different times of the day.

Unfortunately, car traffic has yet to figure out the reduced speed; watch the large queues of stop-and-go cars cruising at 25-30 mph, just to stop and wait at the red light. They do this on every block, and this negates any savings in fuel consumption. The MTA may want to install signage advising drivers to drive at 15 mph or take another route.

By: marcos

marcos — Mon, 02 Mar 2009 20:24:37 +0000

My recollection was that in 1997, when the Valencia Bike Lane was first installed, it was environmentally cleared with a mitigated negative declaration and the mitigations (LOS!) were retiming of traffic signals.

In the absence of an ATG or VMT metric to replace LOS, one would wonder how the MTA can take this step without crossing their own current standards?

-marc