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Archive for July 24th, 2015

Traffic Signal Timing: Burnett Blvd. at Rt 55

Adapted from an email to NYSDOT (hvtmc@dot.state.ny.us):

The minimum green and yellow times on the signals from Burnett Blvd to Rt 55 are too short for bicycle traffic making a left turn across six traffic lanes.

The pictures show key points from our ride on 2015-07-10, returning from the Balloon Festival in Poughkeepsie. We took the DCRT around Poughkeepsie, went through Arlington to Rt 376 at Collegeview, then took Rt 376 Red Oaks Mill.

The image sequence numbers identify frames extracted from video files. The front camera (a Sony HDR-AS30V) runs at 60 fps and the rear camera (a Cycliq Fly6) at 30 fps, so you can directly calculate the time between frames. The Fly6 timestamp is one hour ahead, for reasons I don’t quite understand.

The red signals are turning off and the greens haven’t lit up yet:

Burnett at Rt 55 Signal - Front 0196

Burnett at Rt 55 Signal – Front 0196

One second later, the car and our bikes are starting to roll:

Burnett at Rt 55 Signal - Front 0260

Burnett at Rt 55 Signal – Front 0260

Given the number of drivers blowing through red signals at full speed, devoting one second to watching for oncoming traffic seems prudent.

The yellow signals begin turning on seven seconds after the green:

Burnett at Rt 55 Signal - Front 0633

Burnett at Rt 55 Signal – Front 0633

The car has reached the pedestrian ladder across Rt 55, but we’re still crossing the westbound lanes of traffic. Note that I’m lined up with the lane closest to our starting point on Burnett: this is a big intersection. We may not be the fastest riders on the road, but we’re not the slowest, either.

We’ve reached the far side of the intersection just under 16 seconds from the green:

Burnett at Rt 55 Signal - Front 1142

Burnett at Rt 55 Signal – Front 1142

However, the opposing signals turned green while we’re still crossing the eastbound lanes of Rt 55, 15 seconds after the Burnett Blvd signals went green:

Burnett at Rt 55 Signal - Rear 0408

Burnett at Rt 55 Signal – Rear 0408

About 2.7 seconds later, cars have been accelerating across the intersection toward us as we reach the pedestrian ladder:

Burnett at Rt 55 Signal - Rear 0490

Burnett at Rt 55 Signal – Rear 0490

They started rolling immediately after their signal went green; waiting a second isn’t a universal practice.

Setting the minimum Burnett green to 12 seconds, the minimum yellow to 10 seconds, and the minimum delay from Burnett green to Rt 55 green to 30 seconds would help cyclists (just barely) reach the far side of the intersection before opposing traffic starts rolling.

As a bonus, adjusting the sensor amplifiers on Burnett to respond to bicycles and marking the coil locations on the pavement in both lanes would help us through the intersection during low-traffic-volume times, as our bikes seem unable to trip the signals.

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