BIKEPGH MESSAGE BOARD ARCHIVE

« Back to Archive
24

PG: CMU stoplight synchronization works

article here.


it would be interesting to see a study on how this plus bike lanes affected traffic congestion through an area.


hiddenvariable
2012-09-24 17:34:19

hmm, I keep seeing this reposted... but my anecdotal experience is that the new traffic lights in the area surrounding target are terrible. If anything, the three lights on penn circle east seem to be synchronized to turn red in series. Just yesterday I had this happen to me after turning right onto PCE from Penn Ave.


dmtroyer
2012-09-24 17:41:00

Synchronization on Pittsburgh traffic lights. HA! Entertaining.


lou-m
2012-09-24 18:32:36

just hope this doesn't make light change out of turn at a whim, sometimes i rely too much on known light rotations


imakwik1
2012-09-24 19:47:29

Do the lights around Target in E.Lib change their timing based on time of day? During rush hour it seems like I get every light red from the end of Centre Ave all the way to Bakery Sq. If I go through there on a weekend or around 10:00am I can usually go through all green lights.


I'm all for adaptive signaling. Sitting at a light, wasting gas, waiting for no one to go by is a pretty annoying 1st world problem.


roadkillen
2012-09-24 20:29:14

This just in....water is wet.


rice-rocket
2012-09-24 21:08:14

my way-back machine takes me to 2002 when then city traffic engineer, Darryl Phillips, was putting a young intern to work on the CTRTCS. Poor me didn't know Microsoft dBASE, but the Point Park feller did...


CTRTCS was and still is to be the most epicly smartest of electronically controlled traffic signal grids.


Mr. Phillips is now getting paid what he's worth from PB Americas to develop Pittsburgh's BRT System from downtown through Oakland and into the Eastern neighborhoods.


sloaps
2012-09-24 21:44:55

Roadkillen- When I cross penn from the direction of pizza sola going toward target on my commute home on Penn Circle East, I count the number of seconds between my light turning green and when penn ave turns red, and it is always 15 seconds.. No matter the time of day..no matter the amount of traffic.


stefb
2012-09-25 00:19:27

Does this system detect bikes? Does it handle bikes at the front of the queue with cars behind properly? If they expand this, will they finally pave the craters in front of whole foods?


benzo
2012-09-25 12:59:25

Those aren't craters, they're traffic calming devices.


reddan
2012-09-25 13:14:13

It seems pretty obvious that if all your metrics are based on cars, you're likely to end up with a place that's fine for cars but terrible for anyone else. I don't know if the planners are ignorant of that, or if they simply don't care, but either way this is not progress. I spend a lot more time walking around that area than I do in a car (or even on a bike), and it completely sucks. It takes twice as long to walk anywhere around there as it should because of how crappy the lights are set up.


(from the "Pittsburgh City News" email I got today):


The Traffic21 Initiative has proven to dramatically reduce vehicle emissions and long travel times in the bustling Penn Avenue and Penn Circle intersection - home of East Liberty’s Target store - where vehicle wait time was reduced by an impressive 40%. This technology is the most sophisticated in the world and will soon be deployed to more City intersections.


salty
2012-09-25 19:32:15

increase vehicle wait time enough to encourage people to walk or bike. THATS how you create a truly bustling business district. foot traffic = sales.


cburch
2012-09-25 19:43:30

But if you can prove vehicle emissions are reduced because idling was reduced, then you can apply for federal CMAQ funding to install new signals instead of bike and pedestrian infrastructure.


sloaps
2012-09-25 21:37:37

penny wise, pound foolish. reduce emissions in a small area, but promote more driving that increases them overall for the region and as a by-product turns a thriving business district into a ghost town with a through road.


cburch
2012-09-25 21:40:35

@sloaps, the law of unintended(?) consequences strikes again.


Personally I'd like to see a concerted effort to disabuse drivers of the notion that they should be able to make good time in a car on city streets. They don't just feel entitled to the whole road...they feel entitled to not be delayed. That's fine on the interstates, but on city streets some people would get a lot less ragey if they just accepted that it was going to take a while to get anywhere.


2012-09-25 23:35:40

I'm not a traffic engineer or anything, but if I start out at 16th and Liberty in the Strip and exactly stick to the posted speed limit I usually get to the Bloomfield Bridge without having to stop.


This stuff does follow some plan...


ahlir
2012-09-26 01:47:57
CMU, Pittsburgh's Surtrac program aims to ease traffic congestion "Stan Caldwell, executive director at Traffic 21, said research continues about how to get signals to respond to pedestrians and bicycles. In the meantime, the technology can spare municipalities the work of re-timing signals based on growth or development." http://triblive.com/news/allegheny/8408616-74/traffic-signals-technology#ixzz3bFZQkys7
marko82
2015-05-26 08:16:33
I often come down Beeler, left on Forbe and right on Maggie Morrison. If I ahve agreen light entering Forbes, I will get a red light on Maggie M. Usually, it turns red about 2 seconds before I get there. Just sayin' I think they should have light cycles that go 23 or 24 mph in 25 mph zones. On 5th Ave, if you go through a yellow light at Bellefield, you can cruise maybe 40 mph to get to the Birmingham Bridge, without the lights slwoing you down. I suspect it's cycles to 30 mph or maybe higher. "Preponderance of traffic". meh.
mick
2015-05-26 14:06:21
You can take the walkway through CMU from Beeler/Forbes to M.M. Students do it all the time. Maybe that timing reflects some other, higher, design goal: The inscrutable Tao of traffic engineering... hidden from muggles like us.
ahlir
2015-05-26 18:43:05
@stefb 15 seconds must be the length of green for the lights on Broad and Center as well, behind target. Literally, often only one car can go at a time before it goes to red. I wonder if they're measuring cross streets like that.
sgtjonson
2015-05-27 12:42:59
Yeah, they really need to adjust the parameters on some of those intersections, especially the broad and center light.
benzo
2015-05-27 14:57:55
"Rapid Flow Technologies LLC, which has helped reduce traffic delays in the busy East End neighborhood, is being recruited to do the same on the North Shore. ... Rapid Flow, a Carnegie Mellon University spinoff, developed Surtrac adaptive traffic signals." http://www.cmu.edu/cie/news/2015/october/pittsburghs-north-shore-traffic-gets-critical-look.html "The company... has installed the technology at nearly 50 signals in East Liberty. Since the first ones were installed in the heart of East Liberty in 2012, traffic studies showed that vehicle wait times dropped by 42 percent, travel times by 24 percent and vehicle emissions by 21 percent." For pedestrians, "if you push the [call] button, it doesn’t get you there any faster. But what happens is, if you do push it, it will make sure it gives you enough green to make it across the street safely. In Steve’s new version of the system, those call buttons could actually make your waits shorter. And probably not too long from now, those crosswalk signals will just already know you’re there." http://www.alleghenyfront.org/story/pittsburgh%E2%80%99s-smart-traffic-lights-are-taking-bite-out-vehicle-pollution
paulheckbert
2015-11-01 07:30:34
if you push the [call] button, it doesn’t get you there any faster. But what happens is, if you do push it, it will make sure it gives you enough green to make it across the street safely
I hate these beggar buttons. It does get you there faster. You won't get a walk signal at all unless you push the stupid things, and not until the next cycle. Screw Rapid Flow. I bet they've never spoken with a pedestrian before or after their stupid implementations.
dmtroyer
2015-11-02 00:21:02
I posted a comment there, but we've been hearing about making the system better for pedestrians for years now with no improvement. The city should have put their foot down from the start and insisted at the very least that there was no detrimental effect on pedestrians, and ideally reducing pedestrian waits should have been the top priority. Also, it's not just pedestrians but cross-traffic as well - I have the misfortune of crossing two Surtrac intersections the "wrong" way twice a day on my bike, significantly lengthening my commute (I'm working on extracting some data from my GPS tracks about that). But, you know, "CMU startup reduces air pollution" makes for much better press than any of that...
salty
2015-11-02 01:03:15