Friday, November 18, 2011

Traffic Signals and Their Role in Congestion and Placemaking

Great couple of posts on Traffic Signals, yet the perspecptives on signal timing are about more than 10 years old from the Portland viewpoint. We've had transit priority since 1999 and the signals never leave coordination. LRT preemption isn't terribly novel and the staff in Portland are continuing to work with our software vendors on ways to make it more effective.

The article that inspired this are here:
Fighting Congestion in Minneapolis on a Tight Budget
It's not about fighting congestion, it's about taking a look at the policy and determining the best solution given the desired outcomes. Do you want people to take bus, should transit be a competitive mode, if so, manage congestion, don't fight it is a philosophy that has been employed in Portland.

Can Traffic Signals Ease Congestion Without Discouraging Walking?

Yes, Downtown Portland is the perfect example of this, we progress traffic in one direction on our one way street grid and pedestrians in the opposite direction. Does everyone know this? No, but at least we're trying to make it so that half of the time when you're walking downtown you're delayed less than you would be otherwise. We also limit delays to pedestrians by keeping the cycle lengths low, which with short blocks (260' in downtown) is important to reduce the amount of gridlock (traffic queues spilling back between intersections) that occurs during the peak traffic hours. Portland doesn't accomplish this during the typical weekday, but that is life in the big city.

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