The Work Zone ITS Blog – Post #100

canstockphoto4235293This is post number 100 for the Work Zone ITS Blog. So I hope you will humor us as we celebrate this milestone and look back on the past few years in our industry. The blog began in August of 2012. The goal was to initiate a conversation on work zone ITS. We imagined lots of public comments and a lively discussion on topics of interest. That has not been the case. Too many of you are shy or prefer to keep your opinions at the unofficial level. And that’s OK.

It has been well worth doing anyway. We get lots of comments, but they are back channel rather than public. Many of those have led to additional posts. So thank you all for that help.

Our industry has changed significantly over these past four years. Acceptance of work zone ITS is greater than ever before. We have gone from a deployment here and there to required use in states like Texas. Other states like Illinois and Indiana are now using systems on most major projects. Many more states are ramping up their use of these systems, as well.

Manufacturers have come and gone. Some that are still here have changed their business models. Most manufacturers now understand that a local presence is important to provide agencies with fast, frequent service of their systems. So those manufacturers are building relationships with local contractors.

The technology has proven itself. LEDs, batteries, solar systems, and digital communications have all greatly improved. In particular, 4G modems and the cost and availability of satellite communications have made great improvements. Those improvements have resulted in systems that are easy to deploy and super-dependable while reducing costs at the same time.

Our systems will continue to evolve, adding more features and seamlessly integrating with other systems and devices. Work zone ITS is already very cost-effective. Pricing may continue somewhat lower, but most cost reductions will come at the contractor level as they amortize their fleets and learn what their true costs of deployment are.

New challenges lie ahead, especially with regard to automated and autonomous vehicles. There is a lot of talk about our place in that new world. And as that becomes clearer, it will be interesting adapting our systems to help guide driverless vehicles through our work zones safely and efficiently.

Finally, as we start 2017, I would like to thank those of you who have been here since the beginning. You know who you are. About 25 of us have been in this more or less from the start. That group includes manufacturers, contractors like Road-Tech, and some state DOTs. You are the true believers and it is because of your vision and hard work over these many years that have made this all possible. We have a bright future ahead of us and we look forward to working with you all.

Why Aren’t Queue Warning Systems Used On Every Project?

Those of us that have been in the work zone ITS industry for several years understand that agencies don’t change quickly. New technology must be tested and evaluated before it is used on a more regular basis. We get that. But we are now at the point where queue warning systems should be included on every project where frequent and dynamic queuing is expected.

WZcrashesStudies by the Texas Transportation Institute have shown a reduction in rear end crashes of as much as 45%. Crash severity is reduced as well. Other states including Illinois have also seen a dramatic decrease in crash frequency and severity.

These systems are inexpensive and the benefits are substantial. Avoid just one lawsuit by using queue warning and that savings will more than pay for the cost of the system. So it does not matter how long the project lasts. Projects lasting only a few days could deploy a system for something like $700 per day.Projects months long would pay something like $10,000 per month. Those prices include the sensors, message signs, communications costs, design, set-up, etc.

One law suit will cost tens if not hundreds of thousands of dollars.  It really is that simple. And that doesn’t take into account all of the other benefits. Fewer crashes mean the project is completed faster. Motorists are happier with the DOT because they aren’t experiencing long delays. And you will have the data to meet the Federal Work Zone Safety & Mobility Rule requirements for work zone performance measurement.

There has been progress. Texas is moving toward statewide use of queue warning systems. Illinois is also. Several other states are working on following suit. But most states only use them on special high impact projects. Some don’t use them at all.

So, I really do want to know. What is holding you state folks back? Why don’t you use these everywhere? I sincerely want to know. Please comment on this post. Let’s talk about it. Perhaps as a group we can find ways around the road blocks you face. And together we can significantly reduce the single largest cause of work zone fatalities nationwide.

Variable Speed Limit Signs

VSL UtahAt the recent National Rural ITS show held in Utah, a workshop was presented on the subject of variable speed limit signs. The speakers included Lynne Randolph from the Southwest Research Institute who talked about VMS use in Texas, Brian Christensen of Horrocks Engineers and Glenn Blackwelder of Utah DOT who discussed the local VMS installation on I-80 between Salt Lake and Park City, and Josh Crain of DKS who talked about the use of VMS in Oregon.

This technology remains one that makes good sense in theory, but whose complete affect on traffic is still not fully understood. This workshop filled in some of the blanks but there is more work to be done.

In short, a variable message sign system measures traffic speeds as conditions change and then displays the 85th percentile speed rounded down to the nearest 0 or 5 on regulatory speed limit signs upstream. The idea is to smooth traffic flow and reduce the speed variance that occurs as drivers begin to respond to changes in weather, traffic volumes and construction work.

The speakers shared some interesting lessons learned. Utah’s installation seemed to be the most successful. They have a total of 15 VSL signs through Parleys Canyon, a very steep climb from Salt Lake City east to Park City. There are 8 signs eastbound and 7 signs westbound. The other deployments discussed had far fewer signs or in Oregon’s case, they are single installations spread over the state.

Utah also posts VARIABLE SPEED LIMIT SYSTEM AHEAD signs at each end of the canyon. For these reasons they are far more visible and, I suspect, gets better results.

Utah did find that the white LED displays washed out behind a sign covered in the standard white reflective sheeting. To overcome this they added a black band around the speed display. You can see in the photo above that this change greatly improved the contrast so the signs are now easy to read in all light conditions.

The four speakers seemed to agree that drivers were more inclined to respect lower VSL speed limits when weather or construction activity justified the change. They did not respond as well when limits were lowered due to congestion downstream. Drivers need to know why they should slow before they respond.

Utah’s signs are enforceable. Texas’ signs are not. Oregon has installed some of each. They have developed a decision tree that weighs local conditions and the reasons for the installation to determine which type should be used in each situation.

It was a very informative workshop. I encourage you to download it when it becomes available.