Explaining WZITS Value to Non-Practitioners

In my past two posts we discussed two common themes from the FHWA Peer-to-Peer exchange held May 21st and 22nd in Iowa. The people who participated shared their thoughts and frustrations associated with work zone ITS deployments and there were several common themes.

The third one we should discuss is the difficulty we all have explaining the value of work zone ITS to systems operations folks, director level leadership, and others who lack work zone experience. Often, these non-practitioners are the people who must approve the use of and expense of a work zone ITS system before it is included in the TMP. Participants wished they had a better way to explain how more work zone data results in increased safety, increased throughput and lower societal costs.

This goes back to the problem I discussed in Some “Get It” and Some Do Not (10/1/12). In that post I repeated what Jon Jackels of Minnesota DOT told me. He explained that unless someone has extensive work zone experience, he or she won’t understand work zone ITS. It’s like having the best tools but no idea of how to use them.

In one way, this is a classic Catch 22 scenario. You can’t prove the value of the system until you have better data. But you can’t collect better data until you get a system in place. There is also the need for good baseline data we discussed in the past two posts. Without it, it is difficult to measure the systems effectiveness.

But we must find a good way of explaining it. I believe there are at least five points you should make:

1)      If we know where the queue starts, it might point out needed changes in the traffic control. For example, if the queue begins at the taper, perhaps you need more signs or PCMS encouraging drivers to merge early.

2)      More sensors result in faster notification. Faster notification results in a smaller problem, fewer secondary crashes, and faster EMS response.

3)      These systems help us meet the requirements of the Work Zone Safety & Mobility Rule to track work zone performance and adjust as needed.

4)      When public, project specific websites are part of the system it increases driver awareness and reduces their frustration.

5)      These systems make sense to drivers. They appreciate the effort. Texas DOT and TTI got a very positive response to their recent efforts on I-35.

In short, when these systems are deployed properly they will result in improved safety, fewer incidents, better throughput, and a reduction in societal costs several times greater than the cost of the system.

What have I forgotten? Please comment with your ideas. We would also love to hear your stories, both good and bad, when you tried to explain the value of work zone ITS.

Making Better Lane Closure Decisions

In my last post we discussed the general importance of collecting work zone data before any temporary traffic control is installed. This was mentioned as an important lesson learned by several of the states that attended the peer-to-peer exchange May 21 and 22 in Iowa. They all wished they had accurate baseline measurements with which to compare.

In a later presentation W. D. Baldwin of HDR Engineering advocated the same thing but for different reasons. He said that by collecting baseline data before construction begins you will make better decisions about when to take a lane.

He suggested watching traffic counts. He uses PCE’s (passenger car equivalents). Most freeway lanes can handle about 1600 PCE’s per hour before queuing begins. If you measure counts over all lanes before you close one or more lanes, you will be able to see if the resulting counts will approach that number in the remaining open lane(s). If so, you should delay the work.

Many construction projects are bid with pre-planned work windows. These are traditionally based on historical data. But as we discussed in the last post, counts often differ significantly due to a variety of reasons. Mr. Baldwin explained that by measuring counts just before you start, you will make far better decisions about when to close lanes and when to open them back up.

This may be especially important for maintenance work and other short-duration work zones. Maintenance crews could place a sensor near the start of their proposed taper when they arrive at the work location. They could then hold their tailgate meeting with the crew to discuss that days’ work while the Traffic Management Center monitors counts. As soon as counts are low enough, the TMC could call the supervisor and tell him it’s OK to close the lane.

The other side of this same coin is some form of variable work windows. Utah DOT is considering a system of incentives or disincentives where the contractor decides when to work and when to stop. They are penalized when speeds drop below a certain level, or when queues exceed some agreed length, or some other measure is exceeded.  Both the DOT and the contractor see the data in real time so everyone is on the same page. It gives the contractor the opportunity to get more done when traffic thins out.

In cities like Los Angeles and San Francisco work windows can be as little as 4 or 5 hours. Traffic control takes a good hour to set up and tear down leaving the contractor as little as 2 hours to work. In cases like these, if a variable system got him just one more hour twice a week, it would equal a 20% increase! That would result in faster completion and reduced exposure – increased safety and reduced costs – a “win-win” in anyone’s book!

Due Diligence

A vendor just told me a story. He recently spoke at a meeting with state DOTs and afterward one of them stopped him to say, “You are right. These systems will save us money and they will save lives. We should have them on every project.” He went on to add, “I don’t care about data. I just want the system to work.” This vendor told the man he was wrong. His explained that unless you know the data is coming through on a consistent basis and that it is accurate, it is not a safety system. It doesn’t just need to gather data and act on it. It must do so correctly.

He used queue warning systems as an example. The system must change message signs upstream at the right time and with the correct message or the system is not improving safety or efficiency. This is yet another reason why agencies can’t just include a work zone ITS system in the traffic management plan and then call it done. They have to perform their due diligence. And that means wading into the data.

This doesn’t need to be a big deal. First check to see that data is flowing in on a regular and timely basis. If there are large gaps, they could result in warnings that arrive too late to do any good. Then look at the times when it showed slow traffic and find ways to confirm the average speeds shown at that point in time. Check the logs to be sure the message signs changed when they were meant to do so. After you have done this two or three times, you will find its not difficult to do. And you will be far more confident that the system is working as designed and that you are getting what you paid for.