Monday, August 29, 2011

Transit Signal Priority - circa 2009

Time to dust off the old transit toolkit, I have an opportunity to work on some transit signal priority applications, so after performing a quick google search I found the following:

2009 Presentation at the ITE Annual Meeting
'via Blog this'
2008 ITE Journal Article: Improving the Application of Transit Signal Priority Using the NTCIP 1211 Standard
2007 Presentation by a Partner Firm (a photo taken in DC) is in there
2006 Journal of Public Transportation Article : An Evaluation of Comprehensive Transit Improvements— TriMet’s Streamline Program

conferenceproceedings Dorado, M., Qureshi, E., Hwang, R. and Bertini, R.L., "Measuring the Effects of Traffic Congestion On Transit Signal Priority Call Distances" Canadian Institute of Transportation Engineers, Quad Conference, Vancouver, B.C., April 7-9, 2005.
presentation Dorado, M., Qureshi, E., Hwang, R., "Measuring the Effects of Congestion and Request Location on Transit Signal Priority" Canadian Institute of Transportation Engineers, Quad Conference, Vancouver, B.C., April 7-9, 2005.
presentation Pangilinan, C. , "Using Hardware-in-the-Loop Simulation to Evaluate Signal Control Strategies for Transit Signal Priority" Transportation Research Board, 84th Annual Meeting, Washington, D.C., January 2005.
journal Byrne, N., Koonce, P., Bertini, R.L., Pangilinan, C. and Lasky, M., "Using Hardware-in-the-Loop Simulation to Evaluate Signal Control Strategies for Transit Signal Priority"Transportation Research Record: Journal of the Transportation Research Board, No. 1925, Transportation Research Board of the National Academies, Washington, D.C., 2005, pp. 227
2003 Summary of Implementation Issues for TSP given at October IMSA Meeting

Left Turn from the Cycletrack

Dutch design continues to be something I review every so often when I am considering design choices. It is clear that the land use is very different than the American context. The pedestrian design at this particular intersection is less than desirable and the use of four legged intersection is less than we have here which presents significant opportunities that don't exist with a more complicated situation.
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Friday, August 19, 2011

Bicycle Detection: Inductive Loops or Push Buttons? What do Cyclists Choose

We have an approach to the signal at NE 7th & Broadway (the southbound direction) where there is an exclusive right turn lane and a through movement (no left turn onto the one way street). We have placed a detector in the through lane and have a bicycle push button. There was a complaint that the sign for the bike button was resulting in people on bikes leaving the through lane to go push the button. The logic was that the sign was directing people to use the button.
Our intern observed the intersection on two separate occasions and found that 42 cyclists had to stop at the intersection to wait to cross Broadway.
79% waited in the thru lane
21% waited in the right turn only lane.
71% of riders activated the light using the pavement marker over the loop
17% used the button
2% used both
10% used neither (cars would activate the green as well).

The riders who did use the button did not seem to have trouble accessing it from the right turn only lane and 80% remained in lane after using the button.

2 out of 42 cyclists violated the signal and went through on red. The average delay was 31 seconds, which would meet standards in the Dutch CROW Manual.

We can do better though and we're exploring whether we can provide a confirmation light on the push button, so if someone on a bicycle is on the detection in the lane, they would know they were detected by the LED being illuminated in the push button. We are also proposing to change or eliminate the sign because it would seem intuitive to most users.

Monday, August 15, 2011

Green Driver Article

The City has provided data to a company in Eugene that produced the Green Driver ap for Android and iPhone.

It has gotten some press coverage and it seems to work well (where we have communication to the traffic signals which is about 65% of them). The article from Bloomberg describes a variety of different companies in the market and is worth a read.

Tuesday, August 9, 2011

Pedestrian Countdown Timers and End of Green

An example where the pedestrian
countdown doesn't agree with the
vehicle signal indication.

I had a request inquiring about why the pedestrian countdown timer can't be used to give information to bus drivers, people riding their bikes, or people in their cars. I have had to give the response a few times, so I figured it was worth posting so I can refer back to it later.  

The pedestrian countdown timers are the new standard for indication of the amount of time that people crossing the street have to clear the intersection. There are many cases when the pedestrian logic in the traffic signal controller does not match the green time for the vehicles (people on cars and bicycles or transit vehicles) and for this reason we can not always end the green at the same time as the end of the countdown timer for the pedestrian indication (the time that we must make the decision to go from Walk to Flashing Don't Walk is obviously earlier than the time we decide to go to yellow).  
I use the countdown timer as an indication of how much time is left in the green at the intersection when I am on the street. That being said, it has to be used in context and I don't recommend that practice, especially if you're approaching an intersection at a high rate of speed. In that case, you should pay attention to the vehicle indications (green, yellow, and red) as this presents the information that is presented for you as a vehicle to obey.