If you are an agency employee responsible for a work zone ITS deployment, there are at least two ways you can handle it. You could write a specification that clearly defines what you want and then stay out of it except at those times when you don’t feel the contractor is performing. Or, you could roll up your sleeves and use the deployment as a way of learning what the system is truly capable of providing and how best to tailor it to your project.
As a system supplier, I have worked with both groups and, in my experience the deployments where agency gets involved have all been far more successful than those where they spell out the requirements and then leave. The reasons for this are simple. No two projects are exactly the same and no two systems have exactly the same capabilities. And only through frequent discussions between agency and system provider are the capabilities and needs aligned in the most efficient and advantageous way.
When we first put a system on the road, we are making an educated guess as to where the sensors should be located, what messages will make the most sense to drivers approaching the work zone, and what trigger speeds fit the situation. I’ve always said there is science in the way a system is designed to meet requirements. But there is always a little art, too, in the way you adapt that design to conditions on the ground. If the agency takes the first approach, it will end with the science portion. The system will work. It will do what they asked, but the agency will not be taking full advantage of all it could provide.
My advice is to get involved. Learn about the art of the deployment. Ask a lot of questions about why the system does what it does.
The best time to start is before the deployment begins. Take charge of the creation of the messages to be displayed and the trigger speeds at which they are to be used. Discuss these with the system provider, with agency folks who know the area, and with the construction folks who can explain the different stages and how each will impact traffic.
Once the system is up and running, observe it in operation. If the CMS messages warning of stopped traffic seem to come on too soon, discuss that with the contractor. Perhaps you need to bump the trigger speeds a little lower. If your people are getting too many alarms, work with the system provider until you are only notified of events you wish to know about and none of the little slow downs that occur in a typical day. By taking a little more time to do this, you will see far better results.
This approach has another big benefit. Once you have gone through this process a few times you will have a far better understanding of what the system can and cannot do. You will know where that type of system should be used in the future and your educated guess about sensors, message signs and trigger speeds will be better educated for your next project.
Finally, you will be able to speak with authority about the cost effectiveness of using the system to mitigate traffic impacts. When it comes time to defend that expense, you will be able to do so citing benefits you have measured on previous jobs.