Thursday, July 10, 2008

Northstar Traffic Control System in Montgomery County Texas


Montgomery County Precinct 3 is leading the pack in managing traffic in densely populated unincorporated areas. Our county’s progressive role in the regional management of traffic has gained much momentum. We have a state-of-the-art traffic management system called Northstar. It is really slick! Click here to see the current locations of all Northstar-managed traffic lights in Montgomery County.

Each location has one or more cameras, a control box and of course the traffic lights themselves, linked to the control boxes. The way this works is each camera monitors a street location. It determines if the light should change by several factors - detecting cars within programmed rectangles, a pedestrian-requested light change, time from last change and oncoming emergency fire trucks. This process will be more detailed in the article on traffic light synchronization.

This brings us to inter-connectivity of the intersection management system. Fiber optic cables are installed for each location. We now have 150 miles of cable supporting these systems. There is a dedicated fiber required for each control box. That is how the video is streamed to the central location at the precinct headquarters and how we are able to watch the videos from our workstations. One person is located in the control room constantly monitoring the traffic flow and overseeing the operation of the equipment. Soon there will be two persons assigned to this duty as the workload will be greatly increased.

A fiber optic feed is also provided to the county's emergency control center in case of emergency evacuations or incidents. For cost efficiency, there is an agreement to share fiber cables with TxDOT. When the county must install a fiber cable to support an intersection control system, the sharing is in reverse. Precinct 3 is now developing a loop configuration so that there is a backup communication route in case of a cable outage. This entire system will be utilized county wide as it is expanded beyond the confines of precinct 3. Several cities nation-wide are looking at the deployment in our precinct, because we have used innovative techniques to utilize the best of specialized cameras but non-proprietary computer equipment. Cost efficiency is key to the success of this county’s program for management of intersections, including the ticketing of red light offenders.

What is the future of this technology? For sure the deployment here will be expanded. Within two years, there will be 500-600 units operating in the county. Additionally, the violation cameras will be expanded to key intersections. These cameras are also capable of determining the speed of individual automobiles. If there is a speeding car behind one that is not speeding, it is possible to miss the detection of the speeding car. This is the only known flaw with the camera. Otherwise, the county is positioned to issue citations for speeding if the legislature will permit the practice. Why start issuing speed tickets by the camera method? "It is much safer than a police officer issuing a citation along the roadside where traffic movement is impeded by the issuance of a traffic ticket" noted Ed Chance the commissioner. It is the the rubberneck effect. Is there an issue of privacy? If someone is speeding (usually 11 MPH over the limit), defined by criteria for the camera’s location, the camera will set off a photo. If not, there is no photo taken. Break the law; county takes a photo – no invasion of privacy. If a policeman pulls you over for speeding, it is not an invasion of privacy. See the commissioner’s comments on his who’s who page.

When accessing the Northstar website, you can watch any particular intersection you wish. The data is streamed to you at one frame/second. At headquarters, they watch it at 15 frames per second. To view an intersection, simply click on the location on the map that you wish to see. You may have to scroll on the Google map to find the intersection you wish to view. To do that, click and hold down the left button of your mouse over the map and move the map until you see the intersection that you seek.

Weather stations are also being planned for the Northstar system. Bridges sometimes ice up and other times do not, when under a freeze advisory. It would be more cost effective to monitor the bridges electronically for a near freezing temperature and then deploy surface crews, rather than deploy them each time the weather might be freezing. In other words, just in time cost effective ice prevention on each bridge. This is part of the near term planning of the precinct.

Some related statistics might help us to understand our issues and the need for automation. On some days, East Panther Creek and Woodlands Parkway has as many as 75,000 trips logged, a very heavy load. Woodlands Parkway has some 50,000 trips per day as an average. Our intersections are designed for 1900 cars per hour. We exceed that significantly at East Panther Creek and Gosling intersections with Woodlands Parkway. For every automobile running a red light, we have an additional 9 seconds delay for the perpendicular traffic. If 10 automobiles continue through an intersection after the light changes, they have caused as much as a 90-second additional bottleneck for perpendicular traffic.

Traffic speed statistics are regularly gathered in 15-minute windows. On I-45, the average speed of vehicles has been measured as high as 81 MPH in one of these 15-minute windows. Assuming some of them were traveling at 70, then some of them were also traveling at 90 or even 100! On The Woodlands Parkway, peak speed average is a little over 60. That means some traffic is likely moving at 70 MPH or more.

Also noteworthy, we have fewer automobiles on our roads this year than we had last year. This downward trend is what we are looking for. Research Forest and Lake Woodlands expansion projects should continue that load reduction trend on the Woodlands Parkway.

Related short articles to be released soon:

Many thanks to Commissioner Ed Chance and Traffic Manager Fred Koehler for their time to explain the vision of the precinct and county.

1 comment:

Woodlander said...

Excellent article and info! Certainly many obvious safety benefits, with unforseen ones to come. And will be a valuable aid to getting around in the Woodlands when trying to traverse the area during peak traffic times.

Might offer a little help to any who might run into the same problem I did when trying to view the cameras though. When selecting any individual cam on the Northstar site a message would appear saying "Media Control - the media control could not be registered on your computer."

Viewing the cams requires installing an Active-X control named Axis Media Control from Axis Communications. But each time I attempted to download and install the Active-X control I would get into an endless loop with the Internet Explorer Add-On Installer.
I'm running IE7.0 on Windows Vista Home Premium. Went to research the problem in AXIS.COM's support site FAQs. Found the issue is a common one, with a number of suggested workarounds. Tried them all, none worked.

So, closed my IE7 browser and lauched my Firefox browser and lo-and-behold I could access the Northstar cams immediately with no problems.