Cameras or Sensors?

I don’t claim to be an expert on this subject. In fact, I hope to learn more about it from you. But I believe that when you are budgeting your work zone ITS, you are almost always better off putting most of the money into sensors rather than cameras. You only need so many cameras and you probably don’t need any at all. But I’m not sure you can have too many sensors.

In my experience, cameras cost at least three times more than sensors. The device itself is more expensive because it needs a larger trailer, more solar and batteries to power it, and a taller tower. It also costs more for wireless service because it requires much more bandwidth and it requires it continuously, not just for short packets of data. In some cases cameras cost more than 5 times as much as sensors. So, for your money, you can get three to five more sensors for every camera you give up.

We need to better understand both tools before we can discuss the budget. When do we need cameras? Most of the time cameras are used to verify the data from the sensors. Is traffic really stopped? Or was this a false reading? But if you have enough sensors, the ones on either side of the one you are verifying will quickly do it for you. And, they will do that automatically. Just because we can check the data obsessively doesn’t make it a good idea.

But this is not to say we never need cameras. There are some good reasons to have them:

  • Publishing video to a webpage helps drivers check conditions quickly and raises public awareness about the work zone.
  • Emergency response may be improved by viewing the incident first to know just how bad it really is and to direct responders to it in the most efficient way.
  • Some DOTs may want a video record of the work zone traffic control. This is still controversial but whether you agree with the idea or not, it is still a legitimate reason for cameras.

A reason that is less legitimate is the use of cameras to look at ongoing work or to look at locations on the jobsite without having to drive there. This does save time and money, but not enough in itself to justify the cost.

These are some of the questions you should ask yourself when evaluating the need for cameras:

  • Are there permanent cameras at or near the project that can be used?
  • Is the job several miles long? The longer the project, the more important video becomes to groups like emergency response.
  • Will there be several stages to the work? As construction progresses and traffic control is changed, it is important for drivers to know about those changes in advance.
  • Is public outreach a part of your TMP strategy? If so, a web page with video might be an important tool.
  • Will there be lane shifts, narrow lanes, or a significant reduction in capacity during construction? Any of these conditions may result in an increase in collisions. The more problems you expect, the easier it is to justify the expense of cameras.
  • Is this what FHWA calls a “major” project? The larger and more complicated the job, the more likely you are to benefit from CCTV.

Cameras have their uses. But next time you are planning a job, please ask yourself these questions and consider your goals for work zone ITS before you decide to add them to the project. You may be able to do the same thing more efficiently by just using sensors. What do you think? Have I left out important questions? Is there a side to this I have not considered? Make your comments now and keep the discussion going!

Connected Vehicles and Work Zones

Carl Andersen, FHWA’s V2I Communications Program Manager gave a presentation to ATSSA’s ITS Council yesterday on the model deployment that just began in Ann Arbor MI. 3000 vehicles will help measure the benefits and costs for evaluation. If the results are positive NHTSA could begin rulemaking to mandate the equipment in new vehicles as early as late 2013.

We Need a Place to Talk Work Zone ITS!

I have a passion for work zone ITS. And at meetings around the country I have learned that many of you do, too. That is why I have started this blog. We need a place where we can discuss ideas, where resources and lessons learned can be shared, and where we can come together to make work zone ITS as common as cones and barricades. By working together, I know we can make that happen.

When I say “work zone and rural ITS” I generally mean portable ITS. In other words, systems of sensors, message signs, cameras and other devices networked wirelessly with the server. But I would also include permanent but smaller devices and systems most of which are used in a rural application. So intersection crash avoidance systems, curve warning systems, fog warning systems, and other similar products are also in this group.

Many of us are frustrated with the slow growth of this technology. We know it works, but it has yet to be used on a consistent basis. This is due to several factors:

  • DOT decision makers’ lack of familiarity with the technology.
  • Conversely, ITS often falls within the permanent systems area in DOTs and they don’t understand work zones.
  • And, yes, some of it is due to funding and the continual effort to reduce project costs.

So, let’s do something about it. I will write one full post every month. Occasionally I will make other small posts of random thoughts, ideas or suggestions.  Please sign up to be notified when I post a new article.

These are just a few of the subjects I plan to cover:

  • Specifications- good, bad, and in between
  • Travel time versus delay time
  • What are the best metrics for work zone performance?
  • Selling the benefits of work zone ITS to key decision makers.

We will also react to news, agency statements, federal rulemaking, or anything that affects our efforts to increase the use of work zone ITS. I also hope to post articles written by many of you. So please send me your ideas. I don’t just want to share my thoughts – I want to have a conversation. So, tell me what you think. Tell me why an idea will work or why it will not. And PLEASE offer your own posts. This will be much more fun if we all share our ideas.

I want this to be fun and enjoyable and at the same time, rewarding. The direction this takes is up to all of you. There are just a few rules (and I can change them at any time):

  1. Posts and responses must focus on work zone or rural ITS or other related subjects of interest to our group. I love kayaking and good wine but we aren’t going to cover either of those subjects here.
  2. Disagreements must be reasoned and civil. Don’t sugar-coat it, but don’t resort to name calling. If you are right, your argument should stand on its own.
  3. No whining. Venting is OK, but then move on.
  4. Don’t be too serious! Let’s have some fun while we are at it.

Thanks for reading. If you like the idea, sign up now and tell your friends and colleagues. If you don’t, then tell me why. The important thing is to have this conversation. We talk at trade shows but that isn’t enough. It is time to focus on work zone ITS full time until it is used everywhere it is needed.