Today we take up Part 2 in our discussion of work zone data. I’ve written in the past about the things we take for granted as practitioners that we should stress to others. Another of those is the importance of multiple data points within the work zone. Permanent ITS systems measure and report speeds over a segment of roadway. Bluetooth loops, RTMS and cell phone data can all report the time it takes to drive from point A to point B. But when that number suddenly increases, none of them can tell you where the problem is located.
This also is true when evaluating work zone performance. Data supplied by permanent systems may be able to tell us average speeds and volumes, but that only indicates if there was a problem or not. It does not identify that problem.
By placing multiple sensors prior to the work zone and at key points within it, we will immediately know when the traffic slows and where the slow down begins. This has several important advantages:
- It tells EMS where to send the responders, shortening response times.
- It tells DOT where the problem lies in the traffic control. If it persists, they will know to make changes.
- It usually alerts key stakeholders faster, because the system doesn’t wait until the delays reach a level sufficient to trigger an alarm. As soon as one sensor detects slow or stopped traffic, an alert is sent.
- It helps future designers avoid similar problems.
- It logs the incident and helps to better identify it later when matching it up with reports from law enforcement because you will have good idea of where it took place.
In short, permanent systems measure macro segment traffic flow. It gives you the “big picture”. Portable systems are much more granular and offer detail that was not available until now. This micro data is something that most DOTs don’t even know they need, until they have a chance to see it. But once they do, they wonder what they ever did without it!