Cambridge Traffic and Parking is responsible.

Pavement sensors would be a great idea here, but I doubt it will happen, juding by the very small number of lights with sensors in the rest of Cambridge. (I can only think of 5, one of which has had broken sensors for a few years.)

Another option would be for the light to be blinking yellow for the main road and blinking red for the other roads at all times, except when a pedestrian pushes a button. I think this light was installed basically to help pedestrians, since making right turns has never been a problem, and left turns still aren't allowed.

In all fairness, the new light enables people coming from the cinema to make a left turn onto Binney going East (towards 3rd St etc), which we couldn't do before, and that's actually very useful. Unfortunately, it does stop the Binney St. traffic while it does it.

Great light, but the timing could probably be fixed :)

It is true that the WALK sign for all crosswalks comes on every cycle without needing to push a button. We know from experience that most pedestrians are not interested in pushing buttons, so we don't like to use them in Cambridge. The down side of this, though, is that we have to stop some stream of traffic when each WALK sign comes on.

For Binney Street drivers, the good news is that the signals are coordinated, so if you are headed straight on Binney of Galileo, you will rarely stop at Fulkerson.

Jeffrey R. Parenti, P.E.
Traffic Engineer

If functioning buttons lit up when they were pressed, and the city removed the many buttons which don't do anything, pedestrians would learn to trust them.

Another idea: traffic on Binney east (coming from the Cinema) could have a stop sign instead of a traffic light. Then traffic turning left onto Fulkerson wouldn't have to wait for the light. Traffic turning right onto Galileo could share the green with Fulkerson southbound.

Because left turns off Galileo onto Fulkerson aren't allowed, Binney past the Cinema is the only way to get from the south and west to East Cambridge. It's really frustrating that residents have to wait at this long light to get home, when there's no conflicting traffic or pedestrians.

You can't mix traffic controls within the same intersection, i.e. a traffic signal and a stop sign. Keep in mind that land development along Binney Street (construction of which has already begin) will increase traffic along Binney fairly soon. I agree that a signal doesn't make much sense at an intersection where traffic is light, as it the case today. But with 1.4 million square feet of new building coming, the new signal here (and at Second Street) will be needed, and we like to build them before they are needed rather than after.

Jeffrey R. Parenti, P.E.
Principal Traffic Engineer
City of Cambridge

Mr. Parenti,

Thanks very much for your response. Would you be willing to take the look at the
timing and sensor issue again, with real morning and afternoon traffic patterns
at they exist now? There are often many cars waiting at one side or another of
that intersection, with no one using the other (green) direction. Can this be
mitigated somehow?

Best,

Seth

Engineering standard requires me to have the flashing DON'T WALK sign on for a minimum time equal to the length of the crosswalk divided by a design walking speed of 3.5 feet per second plus at least 7 seconds of WALK time. Any green light shown concurrently must be on for the same amount of time. This is why when the side street runs out of cars, the green light stays on. You might be able to see the pedestrian signal counting down the time.

Were this a suburban location with few pedestrians, I would certainly use loop detectors on the side streets, and either skip them entirely or go to yellow after the last car passed through.

This is how I treat nearly all Cambridge intersections. The goal is to make Cambridge comfortable and safe for walking.

Jeffrey R. Parenti, P.E.
Principal Traffic Engineer
City of Cambridge

That is an important constraint/requirement that I was not aware of. Thanks for
the explanation.

This next suggestion may not yet exist, but: if there were a cheap and reliable
pedestrian sensor at each end of the crosswalk -- essentially, a "waiting to
cross" button that would push itself, without any effort from the pedestrian --
would you have any interest in incorporating it into your programming? (I ask
because there may be devices already like this in use in places with advanced
transportation I/T, like Singapore, and there aren't, we can invent them locally.)

Even in a city like Cambridge with many peds, oftentimes there's no one
actually waiting to walk across; so lots of time and gas is wasted by making
motorists wait at red lights anyway.

Thank you.

We have been closely watching the sensor industry. Vehicles are easy because they are made of a lot of metal, bicycles less so, and pedestrians are nearly impossible. We tried a microwave sensor in this neighborhood, on little Binney Street near the movie theater, to activate in-pavement lighting at the crosswalk. But after a few years it was giving a constant call. No sensor has been able to tell of a pedestrian intends to cross or is walking by. I'm sure there is a sensor out there that has the ability, but nothing is close to market ready for our purposes.

And even if there were, I sill wouldn't use them because like regular buttons, it makes the pedestrian wait longer, which works against our goals.

Jeffrey R. Parenti, P.E.
Principal Traffic Engineer
City of Cambridge

Good that you're watching the industry; perhaps something can be developed
that meets your specs.

The logic of your last statement eludes me. How can a button make a ped wait
longer? Wouldn't a button (wired to send the signal to yellow, then red, provided
it hadn't been used in some adjustable X minutes previously) always reduce the
expected waiting time for a pedestrian, compared to waiting for the light to cycle
to red on its own?

Please send all traffic concerns to the city's traffic and parking department. They do not fall under the jurisdiction of the Cambridge DPW. Thank you.

I agree -- if most pedestrians would get a walk light as soon as they pushed the button, then buttons would mean less pedestrian waiting time than a pretimed light.

As far as my suggestion to combine a stop sign and traffic light, how far apart do the streets have to be for it to count as two separate intersections? The stop sign/traffic light setup works just fine at Green/Magazine/River, and Pemberton/Rindge/Mass Ave.

What do pedestrians do in practice at this intersection? I suspect most walk as soon as there's a gap in traffic, even if the walk light isn't on yet.

How often is there a line of cars waiting on one street while there are no cars or pedestrians crossing it? Even within the current guidelines, there might be some retiming that could save time overall.

Nobody gets a turn as soon as they arrive at the intersection -- cars or peds. Say, for example, the light turns green for Binney Street and 2 seconds later a ped pushes the button. It's a poor idea to turn the Binney Street light red (to give the ped a WALK) after just 2 seconds of green. So the pedestrian will have to wait after a minimum amount of time. And since this intersection is coordinated with the intersections on either side (to minimize the number of stops cars make along Binney), that minimum time can be rather lone, particularly in the run hours.

An intersection is defined as anything within the stop bars. If I were to treat this intersection as two, cars would have to stop twice on both Fulkerson and "little" Binney, once for a 'stop' sign (every time), and again for the red light (most of the time) with about one or two car lengths worth of space in between. The stop-controlled intersection would usually be gridlocked from cars waiting for the red, leaving cars tuning right from Binney no place to go. It would be a mess.

Jeffrey R. Parenti, P.E.
Principal Traffic Engineer
City of Cambridge

Thank you for reporting this issue to us. We are pleased to report back to you that this issue is now resolved.

Is there a schedule when traffic lights are suppose to turn red, yellow, green in Cambridge Street: particularly around Green Line/ Lechmere Station…Oh I don’t know: lets just say between 1 to 50 Cambridge Street, Cambridge. Someone, somewhere must have a schedule. I have contacted Cambridge traffic department but Cambridge City Government workers are not known to be the friendliest people, and a call back is not in their agenda.
So, I’m asking on here: where can I find a detail description of time the traffic lights changed colors?
I would appreciate anyone with information with regards to the traffic lights, especially between first and Cambridge Street. Thank you so much for any help

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