Traffic light timing ► Open

• View all 15 Comments
• 

  Seth Teller

  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?

  2012-03-23 · Flag Flagged
• 

  Cambridge DPW (Guest)

  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.

  2012-03-23 · Flag Flagged
• 

  boblothrope (Guest)

  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.

  2012-04-27 · Flag Flagged
• 

  cambridgetraffic

  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

  2012-04-30 · Flag Flagged

• 

  I want to...

  Leave this issue Open Reopen this issue Acknowledge this issue Close this issue

  Attach an Image:

  Attach a YouTube video:

  

  Attach: Photo Video