Trying for all-green signals on Highway 305

The in basket:  Dr. Craig Benson writes, “Perhaps you can help me crack the code of the traffic lights along Highway 305 in Poulsbo. I read in the Sun that as part of the revamping of the 305 corridor the lights were supposed to be timed to provide for smoother traffic flow and less stopping, to save gas.

“Since I live off Hostmark and often shop at College Marketplace,” he said, “I have occasion to pass through all six lights in between at various times of the day and night, sometimes with no other traffic interfering, but rarely at rush hours. I’m pretty sure I’ve never made it through all the lights without stopping.

“I’ve tried setting my cruise control right at the posted limit, a little higher, a little lower, accelerating faster and slower from the lights, everything I can think of to pass through the lights as timed, without success.

“This is an every day occurrence for me,” he said, “and probably for hundreds if not thousands of others – those stops add up! Can you find out from the powers that be what I’m supposed to be doing to get through the corridor without making unnecessary and inefficient stops?”

The out basket: The state gets this inquiry enough that it has posted a discussion of the limitations of synchronization on its Web site, at wsdot.wa.gov/Operations/Traffic/Signals/signal_coordination.htm.

After noting that synchronization requires the same number of seconds for each signal to serve all of its various traffic flows,, it poses a question of itself: “Does this mean I will never have to stop for a red light?”

 

“Unfortunately, the answer to this question is No,” it replies. “There are many reasons why, even when traffic signals are coordinated, you will still have to stop at red lights.”

Among the reasons:

– Pedestrians. Whether those on foot consume some of the time devoted to the various movements  affects the amount of time for other movements.

– Side streets. Even where through traffic is given preference, such as on Highway 305, making for long waits for a green, the goal is to make sure all cars waiting when their queue gets a green light are served. The number of cars crossing affects the main line timing.

– Left turns. The amount of time devoted to them and the number of vehicles waiting to turn subtracts seconds from the main line.

– Two-way traffic flow: Coordinating flows in opposite directions is difficult, especially if the signals in the corridor are spaced differently. “If the spacing is not equal between traffic signals, the green lights may only ‘line up’ well in one direction,” the site says. “When this happens, the green lights will normally ‘line up’ better in the direction with the most traffic. The traffic in the other direction may have to stop.”

– When you drive. Many coordinated system are taken out of synchronization at night and on weekends.

I’ve had to abridge the information on the Web site, for space reasons. Look it up for a more detailed explanation.

 

2 thoughts on “Trying for all-green signals on Highway 305

  1. I was impressed by two vehicles from the fire department at Day Road and 305, I knew they could use their light changing ability and they didn’t, it cost me some time but appreciated them playing by the rules.

  2. This reminded me of my own problem and that of my neighbors.

    For my house and three others on Warren Avenue, the only access by car to is via a one-way alley between 11th St & 10th St. Coming south, it’s a right turn. The alley is narrow and the pavement uneven, especially at the mouth, so the turn must be taken slowly. As soon as I cross 11th St. I engage my turn signal, but many drivers choose to ignore it, riding my bumper or swerving suddenly into my lane from the left, and then acting all shocked and angry when I make the turn. I can’t tell you how many narrow escapes I’ve had from being rear-ended, and the guilty drivers all act like it’s my fault.

    it would be nice if more people would pay attention to the turn signals of drivers in front of them, and no get their knickers in a twist when they do actually make that right turn as signalled!

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