Retiming traffic signals is one of the most cost-effective ways to improve traffic flow, and one with tangible benefits. According to the Institute of Traffic Engineers, comprehensive signal retiming programs can reduce overall travel time by seven to 13 percent. But before you can retime your signals, you need data: you need to know how an intersection is doing now, and how it changes after you’ve made your adjustments.
And that’s where the Click 650 comes in. This in-cabinet device is a great way to manage multiple Wavetronix sensors at an intersection. But did you know it also has some powerful features for gathering and presenting data needed for traffic signal retiming, when used in conjunction with the Wavetronix intersection sensors? Use one or both of the applications in this article to get the data you need for your retiming programs.
Get turning movement counts with SmartSensor Matrix
We all know how important turning movement counts are for traffic signal retiming. Fortunately, there's an alternative to standing at the intersection with counting board in hand: implementing the SmartSensor Matrix and Click 650 at the intersection.
Use the SmartSensor Matrix for this application. This sensor uses a matrix of radars to provide the world’s only true presence detection at the stop bar.
Set up a zone at the front of each turning movement. The Matrix, with its accurate, high-definition detection, will count each vehicle that passes through each movement.
Using SmartSensor Manager Matrix, map each zone to its own counting channel; then, in the Click 650 web interface, map each of those channels to its own outgoing BIU detector channel.
Now you’re ready to view the collected data. The new Graphs feature on the Click 650 gives you two options for viewing the counts from each of those channels:
The Data Summary table (below) shows all collected data in table form. Use the sidebar on the left to choose which interval of time to show data for, as well as which channels. The interface will then generate a table that shows you the total number of events detected on each channel.
The Count Details graph (below) lets you see count data in line graph form. Again, you can choose the interval of time and which channels’ data to display, but this time you can see the how the count data changes over time. You can even choose two datasets to display together, for comparison: for instance, two different counting channels, or the same channel at different times.
Once you have this valuable data, you can include it in reports, or use it in traffic simulation software, such as Synchro, for signal retiming optimization.
Get arrival-on-green percentages with SmartSensor Advance
Traffic signal operators have heard these complaints often: “The light turned red just before I arrived!” Well, as long as you have the SmartSensor Advance and Click 650 at your intersection, you can quickly and easily access real-time data from the Click 650 web interface to check on intersection performance. Arrival-on-green percentage is a great criterion to use when determining if the offset or split needs to be reprogrammed.
Use the SmartSensor Advance for this application. This long-range sensor uses patented dynamic ETA tracking to track vehicles all the way to the stop bar.
Set up a zone around 350 feet from the stop bar. To get accurate arrival-on-green data, the zone should be far enough from the stop bar to avoid queueing traffic reaching it, if possible; this is why the Advance, with its extensive range, is such a useful sensor to use here.
Use SmartSensor Manager Advance and the Click 650 web interface to map that zone to a sensor channel, and the sensor channel to an outgoing BIU and detector channel.
As with the previous section, you’ll use the Graphs feature to view the collected data:
The Data Summary table shows you the AoG% and the number of cycles that passed during the interval of time you chose in the sidebar. You can also use the sidebar to select which channels’ data to display.
The Arrival Profile graph (below) shows you a bar graph comparing arrivals-on-red and arrivals-on-green over the course of each cycle; you can look at a single cycle, or at an aggregation of many cycles at once—it all depends on the interval of time you choose in the sidebar. This is a quick and easy way to verify the efficiency of the intersection and see if improvements need to be made.
Once you’ve made adjustments to the signal timing, you can return to this graph to see how the changes have affected traffic flow.
