Slow traffic may be your own fault
Posted: Fri Mar 14, 2008 8:13 am
There was a study recently about cell phone users aggravating traffic congestion because they do not respond quickly enough in heavy traffic. I assume you'all have read it so I won't link it here. But I saw living proof of it last night.
I went out to observe a problem intersection during the evening rush hour. It is a neighborhood intersection of two 2-lane streets, perhaps the last one many encounter before arriving home. The signal is traffic responsive and can stay green up to 40 seconds, which is enough for 15 to 20 cars. Yet the light was often cutting off after 5 or 6 cars. Meanwhile, traffic backed up 25 to 30 cars deep. Why?
The approach to the signal includes a long upgrade, which levels off about 100 feet before the intersection. If you're stopped on a hill, it takes an extra punch to get moving and up to speed. If you don't react quickly to the car in front of you, a gap opens up. Multiplying this effect over just a few vehicles, we wind up with a wide space opening up about 150-200 feet in advance of the intersection. If you just watch the intersection, you won't even see the problem.The signal is handling all the traffic it "sees". If you stand 200 feet away, the problem becomes obvious. The cars just aren't getting there.
The cell phone connection? Easily 3 out of every 4 drivers were talking on a cell phone as they drove by.
I went out to observe a problem intersection during the evening rush hour. It is a neighborhood intersection of two 2-lane streets, perhaps the last one many encounter before arriving home. The signal is traffic responsive and can stay green up to 40 seconds, which is enough for 15 to 20 cars. Yet the light was often cutting off after 5 or 6 cars. Meanwhile, traffic backed up 25 to 30 cars deep. Why?
The approach to the signal includes a long upgrade, which levels off about 100 feet before the intersection. If you're stopped on a hill, it takes an extra punch to get moving and up to speed. If you don't react quickly to the car in front of you, a gap opens up. Multiplying this effect over just a few vehicles, we wind up with a wide space opening up about 150-200 feet in advance of the intersection. If you just watch the intersection, you won't even see the problem.The signal is handling all the traffic it "sees". If you stand 200 feet away, the problem becomes obvious. The cars just aren't getting there.
The cell phone connection? Easily 3 out of every 4 drivers were talking on a cell phone as they drove by.
