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2 Cars Per Green Light

Original post made by Bill, Amberwood/Wood Meadows, on Aug 27, 2014

Mike Tassano - wondering why the signage for the metering light that controls traffic entering southbound i680 from Bernal cannot be changed to 2 cars per green light instead of 1 car. This simple change would help to keep traffic from backing up onto city streets during the morning commute. BTW the city website that details the planned intersection changes is different than the story that was run in Contra Costa Times. The story in Contra Costa Times had an additional lane added to the on ramp. Whoever wrote the byline for the story had a good knowledge of the problems facing morning commuters. The city story shows only changes to the left turn lane and no changes to the on ramp, i.e. build a bigger parking lot.

Comments (9)

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Posted by simple minds
a resident of Downtown
on Aug 28, 2014 at 8:21 am

bill, that's a good idea. One of the best I've heard on this site.

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Posted by Have you contacted Mike?
a resident of Laguna Oaks
on Aug 29, 2014 at 8:44 am


Do you look to PW for your emails? If you're looking to provide input get an answer, you might try emailing Mike directly:

He's a pretty good listener and pretty good at responding if you actually reach out to him.

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Posted by Mike T.
a resident of Another Pleasanton neighborhood
on Aug 29, 2014 at 10:37 am

Mike T. is a registered user.


The Sunol Boulevard southbound on ramp has the "2 cars per green" sign that your post recommends. The 2 cars per green is used when the metering rate is set at its fastest rate but we still want more cars to enter the freeway at that location. For Example: Lets say we want 1000 cars per hour to enter the freeway. Driver behavior requires that the red last 2 seconds (minimum) and the green last 2 seconds (minimum). Shorter reds and greens results in drivers either not seeing the green or red and sitting for the next cycle. Given this total of 4 seconds per vehicle, a max rate of 900 vehicles is all that a 1 lane meter is able to allow onto the freeway.

For Sunol Boulevard we want to have 1000 vehicles per hour enter the freeway. To do this we need 2 lanes set at 5 seconds red and 2 seconds green, but since we don't have 2 lanes, we set the meter at the 5 and 2 and post the 2 cars per green (although about 25% of drivers fail to go with the 2 cars per green).

Bernal isn't set to the maximum rate yet. I have requested Caltrans increase the rate. On both Monday and Tuesday of this week, however, we experienced a near doubling of the traffic trying to enter at Bernal. This was the result of 580/680 interchange accidents that encouraged vehicles to leave the freeway system to find a faster route through our City. On ramp meters are meant to evenly distribute the vehicles entering the system so that mainline flow interruption is minimized, the metering lights also discourage the cut through (although that is not the intent, it is often a side effect). When this does not happen is when the delay is so extensive on the freeway system that the drivers would rather suffer the meter delay).

Our Caltrans metering crew is very responsive and we will look to increase the rate at Bernal.

Mike Tassano

PS - I agree with the Laguna Oaks resident, it is normally a faster response if you email me directly (although I usually hear about posts on this site if I don't see them myself).

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Posted by Ellen
a resident of Another Pleasanton neighborhood
on Aug 29, 2014 at 10:48 am

This is the most constructive discussion I've ever seen on this site. The question was a great one and the answer is so thorough and seems to make sense. It helps to know all that does in to the decisions being made on the flow of those lights. Thankfully it's a rare occasion I have to get on there during that time of morning but I feel for all the people who do in a daily basis.

By the way, this civilized and productive discussion sure beats all the other ones that usually turn to name calling and the blaming of political affiliations :)

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Posted by Citizen
a resident of Another Pleasanton neighborhood
on Aug 29, 2014 at 11:37 am

Good response and comments about a city issue! Thanks.
Also, there are other avenues to get to 680 South.

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Posted by Bill
a resident of Amberwood/Wood Meadows
on Aug 29, 2014 at 2:59 pm

Thank you Mike for taking time for answering my question. I know you read the Town Square Forum and have been nice enough to provide the city's view for various traffic engineering subjects, so I wrote this piece hoping for a wider audience since undoubtly other commuters have come up with the same question. Suggestion - I would get other commuters' viewpoints as to whether they would rather sit in traffic on the freeway or on city streets. I would rather sit in traffic on the freeway since it is a more controlled environment (we are all in this together sort of thing). Whereas sitting in city traffic that is bumper to bumper through at least three intersections and having to deal with merging lanes is a recipe for people to do idiotic things just to get one car length ahead.

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Posted by Traffic
a resident of Another Pleasanton neighborhood
on Aug 29, 2014 at 11:20 pm

Hi Mike,

I have some friends who live further East (Tracy, ...) and they tell me that 580/680 has been 'bad' for some time (not just due to accidents). They all indicated that they have been cutting through Pleasanton and Livermore for some time. I suspect Bernal is going to continue getting worse, as First Street and Sunol Ramp continue to get worse. Personally, over the past few months, occasionally, I have cut across Pleasanton to get on Bernal ramp, as First Street has been backed up all the way to where Stanley turns right towards Santa Rita. I'm not sure where all the traffic is coming from (There has not been much new building in Livermore, although could they be coming down Isabel from 580, to Stanley, to First Street?), but as of now, some times it quicker to cut over to Bernal, than it is to sit through First Street backup, and then Sunol.

I think it would be interesting to study Mission Bld traffic. As most commuters will agree, 680 North coming from the South Bay is only getting worse. Coming North, some commuters will try to bypass some of the traffic by getting off at the first Mission Exit, and then cut across Mission Bld, and get on 680. The bottom line is that 'both' routes are pretty much backed up. The concern is more commuters will attempt to cut across First Street/Bernal as traffic in the East Bay continues to grow.

Thank you.

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Posted by Tom F
a resident of Castlewood
on Sep 1, 2014 at 7:36 am

How about no metering lights at the Sunol Blvd on-ramp? Since the metering lights were installed, there's about once every month or two a serious collision where someone turns left trying to get on 680 in front of someone heading towards Pleasanton-Sunol Road. The traffic on that section of 680 is already slowed down and metering vehicles getting onto 680 from Sunol Blvd has no impact. On mornings when the metering lights are off, there is no long line of cars down Sunol Blvd. and the traffic flows smoothly onto 680.

Mike T., you may want to get out of your office and spend a couple of weeks actually seeing for yourself how traffic works here metered and un-metered. It's far far better un-metered. You also may want to devise measures to deter all that Livermore and Central Valley trash from overrunning Stanley Blvd and First St. weekday mornings. My suggestion is a Fastrak style system charging non-residents to drive through P-town during commute hours. This will send a lot of people to the 580/680 interchange where they belong.

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Posted by Map
a resident of Del Prado
on Sep 1, 2014 at 12:41 pm

I'm thinking TOLL ROADS coming into town, let's make some money on all this cut trough traffic since we can't seem to get rid of them!! And go back to that idea floating around years ago to make main st. One way only with traffic flowing north to south, that will surely get rid of the afternoon commuters, running stop signs and targeting pedestrians in crosswalks, how about it Mr. T time to step up and get agressive, let's take are town back !!

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