Mike on Traffic

Enforcement Lights on Traffic Signals

Following is a summary of Jerry Kotzenmacher's talk at the May 13th NCITE luncheon.  He talked about Mn/DOT's experience with traffic signal enforcement lights. 

Background
Enforcement lights are added to traffic signals to aid the police in catching people who are running red lights.  Many times the police can't park in a good spot to see the red indications at a signal, the stop bar, and a vehicle simultaneously.  Typically, a police officer needs to sit off to the side of the road and radio an officer downstream of the intersection to catch the red light runner.  The indication light is put in a spot so the officer can have a good parking spot and see everything they need to pursue a red light runner.  The light turns on when the red light turns on.  These systems are starting to be used around the United States because they are safer and require less police staff.  It is hoped they will also act as a deterrent if the public knows they are being used.  Mn/DOT tested a system based on the City of Burnsville's request.

Concerns
A few concerns Jerry brought up regarding the enforcement light.

• The light is adding more of a power draw to the signal which might trick the conflict monitor.
• Will the police use them enough to justify the cost?
• Who will pay for the installation and maintenance (Mn/DOT used a blue LED light - hopefully requiring little maintenance)?
• Although a red light running ticket given using the system was contested an upheld, use of the system hasn't fully been challenged/validated in the courts.
• The installation location needs to be coordinated with the police at the intersection to make sure the light will meet their needs.

Policies
Mn/DOT will not be installing enforcement lights at every signal in their jurisdiction.  They are open to installing more enforcement lights.  Mn/DOT will review police department requests on a case by case basis. 

Accessible Pedestrian Systems

I spoke at this Wednesday's NCITE luncheon about Miovision's automated turning movement count system.  The luncheon had a technology theme.  In addition to my presentation, Sue Zarling with Mn/DOT spoke about accessible pedestrian systems and Jerry Kotzenmacher with Mn/DOT spoke about traffic signal enforcement lights.  Both talks were interesting.  I'll post about Sue's presentation here and Jerry's presentation next week.

Background
Accessible Pedestrian Systems (APS) are meant to aid the sight impaired in crossing intersections that have traffic signals at them.  The pushbuttons have arrows and braille descriptions.  They also make a slight beeping sound to help the impaired locate them.  The system has a sound detector so the beeping fluctuates based on the ambient noise levels.  The beeping stays 5 decibels louder than the ambient noise level.  When the walk indication turns on for those with normal eyesight, the APS gives verbal instructions for the crossings.  It can also give a loud warning if an emergency vehicle is detected by the signal system. 

Mn/DOT has developed a specification for APS.  They have a document online to assist agencies in prioritizing which intersections to retrofit first with APS and they have developed a spreadsheet to assist in the programming of the system.  Also, a very thorough resource for APS is located on walkinginfo.org.

Concerns
A few concerns Sue brought up regarding APS:

• It costs money.  The components alone cost about $5,700 per intersection, not including labor.
• They can be noisy.  They add 5 decibels worth of noise within six to twelve feet of the pushbutton.
• They require additional stub, pushbutton station poles which are prone to being hit by snowplows.
• Each pushbutton is uniquely programmed for its location.  If one breaks, it takes a couple of weeks to get a replacement from the manufacturer.  This is a big maintenance issue.
• You need someone who can read braille to make sure the pushbutton braille is correct.

Policies
There are conflicting judgments and legislation floating around.  In Mn/DOT's opinion, there isn't clear guidance for when APS  must be installed.  The State of Maryland and the City of San Francisco have both agreed to install APS through court settlements.  There are many open cases throughout the country, including in Minnesota, pushing for the installation of APS.  The United States Access Board has published draft guidelines that state APS systems shall be installed whenever new pushbuttons are being installed with a traffic signal. 

Mn/DOT's legal interpretation of all of this information is that each government agency needs to develop a policy for when they will and will not install APS.  They are currently drafting a Technical Memorandum to clarify their agency's position and design guidelines.  In a nutshell, Sue said they will be installing APS with all new signal systems and they are developing a ranking system based on the NCHRP guidelines for retrofitting their existing signals with APS.

Mike Spack Speaking about Miovision at NCITE Luncheon

I'll be talking about my experiences with Miovision's automated turning movement count system at NCITE's May luncheon next Wednesday.  I am going to set up my video tripod camera system for people to see what it looks like and I'll discuss the pros/cons of the system.  If you are in the Twin Cities area, I hope you'll make it to the luncheon.  Here are the details - luncehon flyer.