The Importance of Crash Modification Factors to Work Zone ITS

A webinar was held December 5th on work zone crash data collection and analysis. It was organized by Wayne State University and included speakers from the University of Missouri and Michigan State University. A recording of the webinar will be made available soon.

Several very good resources were made available as the webinar began including “A Guide for Work Zone Crash Data Collection, Reporting, and Analysis” which was produced for the FHWA by the Wayne State University College of Engineering. This guide can be found at:  https://www.workzonesafety.org/files/documents/training/fhwa_wz_grant/wsu_wz_data_collection_guide.pdf

As a work zone ITS practitioner, I have deployed many systems over the years but have very little data to prove the effectiveness of those deployments. The problem has always been establishing a base line of the probable number of crashes given the traffic control, project duration, traffic volumes, etc. Only with that base line can we compare our actual crash numbers to determine whether the system was cost-effective.

The crash data guide states the problem very succinctly, “In order to perform an effective work zone safety analysis, the appropriate work zone crash data needs to be available. The availability of this data is only as good as what is collected on the state crash report form.”

The webinar pointed to several states’ best practices in this regard. At a minimum, states are required to include a checkbox on their form to indicate if the crash was work zone related. But states including Connecticut, Iowa, Minnesota, Pennsylvania and Virginia collect much more. They go into detail about the location of the crash within the work zone, and what types of traffic control and construction activity was in place at the time of that crash.

That data will help them develop Crash Modification Factors (CFMs) for different traffic control treatments. In time we hope to see CFMs for queue warning systems, dynamic merge systems, variable speed limit systems, and much more. Those CFMs could be specific to high volume multi-lane facilities, rural four lane highways, etc.

Once CFMs are developed, the rest of the process is fairly simple. Compare the CFM associated with your proposed system to the traffic volumes where that system will be used, and you will know immediately whether the use of that system is justified. The use of these systems is already taking off, but there is still some guess work involved in the decision to use or not use work zone ITS. By developing CFMs we could speed that process along and make it more scientific.

5G Cell Service and Opportunities for Our Industry

By now, most of you are aware that 5G phone service will be here soon. But you may not understand what that means for our industry. An article written by Hongtao Zhan of SureCall and published recently in VB talks about its potential:

https://venturebeat.com/2017/09/30/5g-isnt-just-faster-it-will-open-up-a-whole-new-world/

As the article points out, download speeds could be as much as 100 times faster than we currently experience with 4G service. This service will be expensive at first but once everyone has switched to 5G devices those faster download speeds could result in greater use of video as data rates eventually decline.

But the most important aspect of 5G for our purposes is latency. Latency is a measure of how quickly critical data is transmitted. 5G offers near zero latency. This will enable an incredible array of new technologies affecting every part of our lives. That is why “Qualcomm is calling 5G the “platform for invention.””

Mr. Zhan describes ways 5G could be used for things like haptic controls in vehicles for purposes such as lane keeping, collision avoidance and more. For our world haptic controls mean we could deploy “virtual rumble strips” in advance of work areas to wake up drivers and perhaps even to return control of autonomous vehicles over to drivers.

Zero latency means workers could be removed from the work area and could perform many dangerous operations remotely using a virtual reality head set and controls. For example, they could “drive” TMA trucks remotely. We might also create a remote control cone setting machine. Striping trucks and RPM installation might also be automated.

How about a phone app to warn workers? With near zero latency, we could create an intrusion warning system that works fast enough to save lives, while requiring very little in additional equipment – just the smart phones everyone is already carrying around. The work area could be delineated on a digital map and any vehicle crossing those lines would trigger warnings to anyone in the area who has downloaded the app.

The possibilities are endless and this new communications protocol is right around the corner. It is time for us to begin thinking about how we might use it to improve safety and save lives.

Work Zone Reporting to Autonomous Vehicles

We just returned from ATSSA’s Midyear meetings in Louisville, Kentucky. The Innovation Council meeting was well attended and included several very interesting speakers. Many topics were discussed but the real focus of these discussions, both during and after the meeting, was autonomous and automated vehicles and how our members can best prepare for them.

Speakers including Dr. Paul Carlson talked about the importance of signs and pavement markings bright enough to be seen and recognized by automated vehicles. AV manufacturers have stated that this is the most important thing we as an industry can do to prepare, at least from the autonomous vehicle perspective.

But from a stakeholders’ perspective – specifically work zone safety – many wonder how autonomous vehicles will know where work zones are located and what they will encounter as they drive through them. This blog has discussed this subject several times over the past few weeks, but given the interest in Louisville, it seemed a good time to review all of the likely ways in which this will be accomplished and consider the advantages and disadvantages of each.

There are at least 6 ways to do this. And by “this” we mean update digital maps in real time. First we must tell everyone where work zones are active. That’s the most important part. For by telling them, those autonomous vehicles can then trigger a return of control to the driver well before the vehicle enters the actual work zone. But ideally, these systems will also include information about that work zone including which lanes are closed, prevailing speeds, and geometric changes including lane shifts, narrow lanes, etc.

So, in no particular order, these are the more likely ways of getting that information out in real time:

Traffic Control Device Automated Reporting

Devices including arrow boards, traffic sensors, flashing beacons, and stop/slow paddles can be equipped to report to a traffic data service or DOT website. This is already being done today. When the device is turned on, it reports its GPS coordinates and the type of work zone. For example, an arrow board, when turned on would report a lane closure. When it is turned off, the device reports the work zone is no longer active.

The advantage of this approach is the activity is truly reported in real time without human input. Another advantage is the location will change as the equipment moves, say for a paving or crack sealing operation. The disadvantage is the need to replace older devices with newer devices that include this feature.

3M Two-Dimensional Bar Codes

This was the subject of a post on August 21st and was discussed by Chuck Bergman of Michigan DOT and Eric Hedman of 3M at the Innovation Council meeting. 3M has installed signs on I-75 in Michigan with two-dimensional bar codes embedded in their sign sheeting. A driver might see a sign saying ROAD WORK AHEAD but infrared cameras in the car would see a second embedded message telling the car to relinquish control to the driver, or to reduce speed automatically to 45 MPH, or any one of a number of other possibilities.

This approach will work well for longer term work zones and ones where the desired message is unlikely to change often. It will likely be low cost and could act as a fail-safe warning to autonomous vehicles. It does not update digital maps simply by installing the signs, but we assume that will be done manually at about the same time.

State DOT Work Zone Phone Apps

Many states require contractors to request lane closures in advance and then to report when those closures begin and end. Some now accomplish this through smart phone apps that make it quick and easy o report in real time.

This is already taking place but it does require someone to key in the closure when it begins and ends. And moving operations won’t be precisely geo-located. Still, it is inexpensive and requires very little effort.

Waze, HERE and other Crowd Sourced Traffic Apps

Users of these smart phone apps can note active work zones and other issues affecting traffic and that information is shared with all other users. This additional information is helpful but depends on users to remain current. Interestingly these apps are beginning to include data streams from work zone ITS systems. So the hybridization of these systems has already begun. And in our last post we noted that Caltrans traffic website known as QuickMap now includes Waze work zone data.

I2V (Infrastructure to Vehicle) Reporting via 4G/5G or DSRC

This was how we originally envisioned the process taking place. A radio of some sort might be installed in advance warning message signs or arrow boards where it would broadcast to approaching traffic to warn of upcoming work zones. These devices might also report slow or stopped traffic ahead. This may still happen, but advances in V2V (vehicle to vehicle) communications both 5G and DSRC make this less likely.

Automatic Reporting by Autonomous Vehicles

AV data collection will “see” and take note of variations of the real world roads from the digital map. This might include some standard deployment of devices in advance of work zones that could be recognized by algorithms to mean a work zone lies ahead.

This has not been suggested that we know of, but autonomous vehicles collect data continuously. That’s a lot of data. Machine learning and sophisticated algorithms will, in time, learn to recognize work zones. Logically those will then be reported automatically as work zones change. This may not occur for many years but it will happen automatically one day.

The change from driven to autonomous vehicles will be a very gradual one. Most experts believe it will take at least 25 years and even then older vehicles, collector cars, etc. will still be sharing the road with driverless ones. Furthermore, the choice of technology to warn of work zones will vary with location, construction activity, project duration, and more. As a result, differing combinations of technologies will likely be used in an effort to reach the greatest number of vehicles and to provide redundancy. After all, as time has proven over and over again, as cars become easier to drive, we become worse drivers. So it will be all the more important that we warn drivers and vehicles of work zones ahead.

Caltrans QuickMap to Add Waze Data

 

Caltrans recently announced changes to their popular QuickMap travel app. The app is available online at http://quickmap.dot.ca.gov/ and from your app store for both Apple and Android. In QuickMap users choose what they want to see, and the area they are interested in seeing, and a custom map shows them exactly that and no more. Travel times and factors affecting travel times such as work zones, weather and other incidents are all displayed in near real time.

They have now added an option to see Waze data. This is significant to those of us interested in work zone ITS because Waze displays iCone sensor data as work zone locations. For example, Road-Tech currently has an iCone system on SR99 in Fresno and the work zone is displayed in QuickMap with an icon of a worker in a hard hat:

Eventually these icons when clicked on will display detailed travel speeds and other pertinent information. That data will help drivers avoid delays and better plan their routes. And in Waze, drivers can add their own information on work zones, crashes and other incidents.

QuickMap is testing the next mobile version in which users can input their own Waze markers directly from QuickMap. It will be one more way to get real-time work zone information to the people that need it most!

Report from the Automated Vehicles Symposium, Part 2

In our last post we discussed the need recognized at the Automated Vehicle Symposium for varying levels of vehicle autonomy based on the road and current conditions. One of those conditions is clearly work zones. A car may be able to operate at Level 4 autonomy in freeway traffic, but may have difficulty ding the same in some work zones.

In those cases we must signal the vehicle to alert the driver to prepare to retake control. And that warning will have to be given leaving sufficient time for the driver to become cognizant of the dangers around his or her vehicle. A poster session at the AV Symposium by Chris Schwartz of the University of Iowa looked at that timing. Their study focused on large trucks and found drivers needed as much as 10 seconds to get their wits about them for normal driving. Work zones should probably allow a little more time, as drivers may have to start immediately to negotiate lane shifts, narrow lanes, or other challenges. So ideally this signal would come at about the first construction area sign (ROAD WORK AHEAD).

The conventional method would occur through the cars digital map. That will be how other hand-offs take place, such as when driving from a roadway capable of supporting level 4 automation to an older stretch only capable of supporting level 3. But those are points that rarely move or change. Work zones may only take place for a few days, or a few hours. As we have discussed in past posts, the map must be updated in real time for features like this to work correctly.

Manufacturers are working today on beacons, arrow boards, and more that will signal when lane closures begin and when they end. This is already happening today and will only become more popular as smart technology is accepted in more and more work zones.

But another option was mentioned in the same session. 3M is experimenting with a way of placing two-dimensional bar codes within their reflective sign sheeting. The bar codes are only readable by infrared cameras. Drivers would never see them. They would just see the static sign saying something like ROAD WORK AHEAD. But the car they are driving would be triggered to return control to the driver.

This technology is in the very early stages of testing. 3M has signs up on freeways in Michigan now and hopes to test more of them in the Bay Area of California soon. It is too early to say this is a solution but it does show promise. A combination of map triggers and these signs would provide some redundancy and might also be a simpler way of notifying drivers of very short term work zones such as those installed by utility companies and smaller agencies.

The good news is that both the traffic control industry and the AV industry recognize the importance of this hand-off prior to work zones and they are working to find solutions.

Report from the Automated Vehicles Symposium

The annual Automated Vehicles Symposium was held again this week in San Francisco. Attendance continues to grow in this TRB sponsored event, topping more than 1500 manufacturers, academics, and other practitioners.

Breakout Session #18 was titled, “Reading the Road Ahead: Infrastructure Readiness.” As the name implies, this session focused on our roads and what must be done to prepare them for autonomous vehicles.

The first section looked at the State of Machine Vision Systems. Both speakers: Jaap Vreeswijk of MAP Traffic Management and Tom Alkim of the Dutch Road Authority talked about results in Europe. They both pointed out road conditions vary from facility to facility and even from one section to another. And for that reason they suggested that a system should be developed to tell drivers what level of automation is supported as conditions change.

This would also apply to temporary changes such as work zones. As autonomous vehicles approach a work zone the driver would be told to take control as a work zone is just ahead. Once through the work zone, the driver could return control to the vehicle so long as that road segment supported it.

The actual mechanics for this process was not discussed. Digital maps could notify us of upcoming changes in the roadway requiring more or less human control. But it could only do so for work zones under 2 possible scenarios: 1) if a local device was placed in advance of the work zone to send out a signal to approaching traffic, or 2) if maps are continuously updated with real-time information…in other words if they have perfect knowledge of all work zones.

That was the subject discussed later in a session developed by Ross Sheckler of iCone. I was asked to deliver that presentation and it was well received. Ross pointed out both the need to place work zones on the digital map, and the fact it can be done today. We are already sharing real time work zone locations and related data with services including Waze and HERE. But we could do so much more if we can just get more sensors out into devices like arrow boards or flagger paddles.

Once we have enough of these in service, motorists and traffic management centers will both come to depend on this accurate, real-time data. And safety will be much improved when even utility workers appear automatically on the map when they turn on their flashing lights.

Combining Queue Warning with Dynamic Late Merge

In our last post we talked about the ATSSA “Tuesday Topics” webinar held June 27th. Joe Jeffrey began the webinar with a discussion of work zone ITS basics. Chris Brookes of Michigan DOT shared some of his lessons learned. The final speaker that day was Ross Sheckler of iCone there to talk about coming trends in work zone ITS. Ross declared that the next big thing will be queue warning combined with dynamic late merge.

Mr. Sheckler began by looking at the state of our industry. He said that nationally there are nearly 1,000 deployments per year now. Costs of these systems are dramatically lower than they once were. And the economy and simplicity of these systems have not affected their flexibility. In fact, because applications vary, flexibility always has been and always will be an important feature of work zone ITS.

And for that reason it is very easy to add features, including dynamic late merge. As Ross pointed out, queue warning systems have their limitations. When volumes increase and queue lengths extend beyond the limits of a queue warning system additional steps should be taken. By instructing drivers to stay in their lanes and take turns at the merge point, it reduces the overall queue length, makes the best use of limited capacity, reduces road rage, and sometimes can even improve throughout.

In his drawings of typical system configurations he listed 4 sensors and 1 portable changeable message sign (PCMS) for queue warning. For queue warning with dynamic late merge he added a second PCMS at the merge point to tell drivers to take turns and a fifth sensor to narrow the gap between sensors midway through the affected area. So, in total, just 1 more sensor and 1 more sign. This is a minimal added cost and significantly increases the capabilities of the system.

The message here is that we can often solve multiple problems with one system. It just takes a slightly different logic in the controlling software. In this case you can solve problems with end of queue crashes and conflicts at the merge point with one inexpensive, easy to use system. So please remember this the next time you specify a work zone ITS system. Consider all of the challenges you face on that project, and think about ways work zone ITS may mitigate one, two or perhaps even many of them.

This webinar covered a lot of ground in a very short time.  It was recorded and can be viewed by ATSSA members anytime at: http://www.atssa.com/TuesdayTopics/Recorded. Or watch for possible future webinars on this same topic.