Data Latency and Work Zone ITS

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We met recently with a large local agency to discuss the idea of connected work zones and the concept of reporting work zones in real time to the digital maps we all use to get from Point A to Point B. She was excited about the idea but had concerns about delays that are sometimes experienced between the time when an incident occurs and the time when it is reported to you by your navigation app.

According to Waze, 65 million drivers regularly use their navigation service to get home as quickly and efficiently as possible. Drivers want to know about problems along their routes before they reach them and in time to take another faster route if it makes sense to do so. Richard Russell, a former sales engineer with Google, said five years ago that, “we actually want negative latency, and will perceive anything less as latency.”

That was about the time that Google purchased Waze. Waze works because users report problems in real time thus helping to reduce latency. HERE has found another way to reduce latency. They look at in-vehicle sensors such as hard braking sensors to identify and locate traffic issues the moment they begin. HERE also plans to begin including user reports to get as close to real-time reporting as possible.

Today, work zones are the single largest cause of non-recurring congestion. So, if we could report work zones in real time (see Work Zone Reporting to Autonomous Vehicles – posted 9/25/18) it will make these services even more valuable. Imagine arrow boards equipped with a device to report location and display status every time it is turned on or off!

Yet how will these services process an unimaginable amount of data including location, date & time, type of incident, and some form of verification and get it to the user without at least some delay? That is a problem only Waze or HERE can answer. We can tell you they are working on it.

In the meantime, some small amount of latency (a few seconds to as much as a minute) is going to exist. But the service is still valuable. In today’s worst-case scenario Driver A leaves home and asks for the fastest route to work. The app recommends the best one based on conditions at that time. Perhaps moments earlier an arrow board was turned on when a contractor closed a lane along that route for maintenance work. A short time later the app reports that roadwork and reroutes Driver A along a now preferable route. The app still saves him time, just not quite as much time as it might have with instant knowledge of all work zones.

Zero latency is the goal. But let’s not allow the perfect to be the enemy of good.

USDOT Roundtable on Data for Automated Vehicle Safety

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On December 7th of 2017 the USDOT convened an interesting group of stakeholders to discuss automated vehicle data needs. The goal was simply to better understand what will be needed, so we can all work in that same direction. Attendees included automakers, regulators, local agencies, privacy advocates, data aggregators including Waze and HERE, universities, and industry.

They have published a short document detailing their findings. Download “roundtable-data-automated-vehicle-safety-report[3585]” here.

A set of four principles was discussed and supported by the group. Those included

  • Promote best practices for data security and privacy.
  • Act as a facilitator to promote voluntary data exchanges.
  • Start out small to find what works and then build on that.
  • Coordinate across modes to save time and money.

Number 2 is perhaps the most problematic. Vehicle and component manufacturers are still playing their cards very close to their vests. They will continue to protect whatever competitive advantage they feel they have. They don’t mind sharing what everyone else is sharing but don’t want to go beyond that point for obvious reasons. So, what will be shared will start with basics such as crash data, AV hours driven, etc. and will grow from there.

The good news, for our purposes here, is the discussion of high priority use cases. #1 on the list is “Monitoring Planned and Unplanned Work Zones”. The data they felt was of the highest value included, “Work zone locations, planned duration of project, updates, planned lane closures, changes in signing, directions, or parking.”

Other encouraging use cases include #2 “Providing Real-Time Road Conditions”. There they discuss the need for data on detours and missing or deficient signs and pavement markings.

Under testing discussions, there was an emphasis on safety-critical scenarios which would have to include work zones. Clearly manufacturers must test not just in ideal conditions, but in all conditions including bad weather, poorly delineated work zones, and in and around major and minor incidents.

They coined the term “Edge Cases” which refer to a “problem or situation that occurs only at the extreme operating parameter.” Certainly, most testing today will continue at or below 35 MPH on a sunny day and under controlled conditions. But once we are all satisfied that AVs can drive safety in ideal conditions, it will be time for the worst-case scenarios. Again, work zones will surely be a part of that.

The last use case of interest was improving roadway inventories. The group felt high-value data for this effort included,””edge-to-edge”, high-definition map elements (e.g., signs and signals, curbs, pavement markings, tolls, express lanes, bridge heights and weight capacities, highway dividers, overpasses, pedestrian areas, bicycle lanes, taxi drop-off zones, (and) quality metrics.”

Under “proposed federal roles” they talk about the USDOT acting as a facilitator of sharing and discussions between the various stakeholders. It’s good to know work zones are now a part of that discussion. Thank you to USDOT for helping make that happen. Our greatest fear just a few short years ago was that the automotive industry would get too far down the road with their development to accommodate special circumstances including work zones, special events and incident response. It’s great to see that won’t be the case.

Are Autonomous Vehicles Safe?

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On February 6th we sat in on a FHWA T3 webinar entitled “Are Autonomous Vehicles Safe?” It was moderated by Dr. Francesca Favaro of San Jose State’s Mineta Transportation Institute. She runs a program known as RISA2S – “Risk & Safety Assessment of Autonomous Systems” and recently examined California DMV data from 2014 through 2016 on crashes and disengagements of automated vehicles.

Because their data is from automated vehicles on the road today, their focus has been on SAE Level 3 automation. That is, by and large, what is being tested now. Most manufacturers are not planning to offer Level 3 vehicles to the general public. But as a result their findings point out the strengths and weaknesses of Level 3 automation. So for that reason most of their presentation came to focus on disengagements – when the vehicle gives control back to the driver – and driver reaction time to those disengagements.

This is an issue of critical importance to work zones. At some point in the future autonomous vehicles will negotiate work zones without need of human input. But that is many, many years from now. In the meantime, a mixed fleet of cars and trucks with varying levels of automation will be passing through our work zones. As Paul Carlson said at the recent ATSSA Innovation Council meeting, “We have had a mixed fleet for some time now. Any discussions of a mixed fleet now are just the next iteration of that.”

So the two related issues of when AVs disengage control, and how drivers react to those disengagements will be an important point of discussion for the foreseeable future.

Their data on disengagements was very interesting. The frequency of disengagements is declining. In fact in 2016 they were one-third of what they were per mile travelled in 2014. So the technology is improving rapidly. Machine learning will continue that trend.

11% of all disengagements were due to external conditions. 49% were due to system failures of some kind. 33% were due to human factors. And 7% to “other”.

Work zones fall within external conditions. 2.22% of all disengagements were due to construction zones and 4.63% were due to poorly marked lanes. Now, we don’t know much about the conditions when and where this testing took place. Speeds were all at or below 30 MPH. But we don’t know if it was dry and sunny, or raining at night. And we don’t know if the time spent in work zones was typical of your average driver.

Chances are they were not. In fact, chances are current testing avoids work zones most of the time so disengagements in real-world work zones would likely be many times greater.

30.12% of disengagements are due to human factors – usually driver discomfort. Some of that is a trust issue with the technology. But a large part is a desire to stay safe in fast changing situations such as near incidents, work zones, or other higher volume conditions. So I think we need to include some of that data as well.

Next let’s consider driver reaction to these disengagements. This is really two issues: what the driver does, and how fast he or she does it. But the study looked only at driver reaction time. The California DMV has not yet defined what is meant by “reaction time” yet manufacturers are required to measure it. So the data presented is inconsistent in its terminology. With that in mind it is still interesting and helps point the way for future studies.

This testing was done in driving simulators. Subjects reaction times varied from 0.87 seconds to as much as 3.17 seconds. Again, that is in a simulator when the test subject was told to expect something. Other studies have shown mean reaction times of 2 seconds or more.

Let’s use the 2 second number, though it may be much higher. At 65 MPH a vehicle would travel nearly 200 feet in that time. A lot can happen in 200 feet when approaching or adjacent to a work zone. So clearly disengagements should occur in advance of the work zone giving drivers time to acclimate themselves to the situation around them. For the next 20+ years many of the vehicles passing through work zones will turn control over to the driver. So rather than try to deal with those within the confines of the work zone, lets’ just automatically turn control over to drivers before they enter it. That will provide a more predictable hand-off in a safer environment.

This study was just their first attempt. As more data is collected and as terminology becomes better defined and as testing ventures into more “real world” scenarios, we will learn much more. We look forward to future reports from RISA2S and other AV research organizations.

A Worker Proximity Warning System

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Late last year a paper was published entitled, “A Low-Cost Mobile Proximity Warning System in Highway Work Zones” by Yong Cho of the Georgia Institute of Technology. It was funded by the NCHRP IDEA program. IDEA or Innovations Deserving Exploratory Analysis is intended to develop and test new, innovative concepts and this paper did just that.

This system is designed to protect workers from moving construction equipment in the work area. Too often we hear about workers killed or injured by a truck or roller backing up or by an excavator swinging around to drop a shovel full of dirt or rock.

The system includes three main components: BlueTooth beacons mounted at various locations on the construction equipment; a pedestrian worker’s PPU or personal protection unit; and the equipment operators PPU. These PPU’s are BlueTooth enabled smart phones with an application designed to “see” the beacons and warn the workers – both the equipment operator and the pedestrian worker when someone is dangerously close to equipment.

The PPU warns the pedestrian worker in one or more user-defined ways: a loud alarm, vibration, or even via a BlueTooth ear piece. They type of warning varies with distance from the equipment. The worker can also define the range at which they are warned since the definition of “too close” will vary with the work being done.

Another interesting feature is the ability of the system to collect data in the cloud for later analysis. It would be a big help when going back to study a close call. And it would help with future internal traffic control plan design for similar types of work.

Best of all, it is very inexpensive costing less than $200 assuming the workers already own smart phones. Tests showed the system worked. The workers who used it, liked it. And they appreciated that the PPU can be worn in a variety of locations and warn them in whichever way they prefer. It was suggested this system be integrated with an intrusion alarm system to offer even more protection.

Read the complete study at: http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=4145

 

FHWA Request for Information Regarding Automated Driving Systems

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This blog just posted a couple of days ago, but this topic can’t wait, so we are posting again today. On January 18th the Federal Register published a Request For Information from FHWA regarding automated driving systems (ADS). It asks DOT’s, manufacturers, trade associations, and other interested parties for their answers to questions in ten specific areas.  Download Docket FHWA-2017-0049. All comments must be received by March 5th, so please get started.

The work zone ITS world should be most interested in questions 4, 5, 9 and 10. You will also be interested in many of the other questions if you are involved in static signs, pavement marking or other permanent roadway safety infrastructure.

First, let’s commend the FHWA for asking these questions. It wasn’t long ago that we worried that automakers and regulating agencies did not know what they did not know. A great deal of time and effort has gone into building coalitions with these folks and it appears that is beginning to pay off.

So lets’ reward their curiosity with well written and timely responses. You can do so individually and/or through your industry associations such as the American Traffic Safety Services Association.

We will start the ball rolling now with these suggested responses to the four questions mentioned earlier. These are short in the interest of time, but should be fleshed out in any formal response.

Question 4: How should FHWA engage with industry and automation technology developers to understand potential infrastructure requirements?

Include work zone ITS providers and trade associations like ATSSA in the conversation. Many of us are already participating in AV events including the Automated Vehicles Symposium, the ITS World Congress, etc. Presentations at these events focused on work zones have lead to many productive conversations and several “ah-ha” moments for AV manufacturers. Please encourage more of this going forward.

Question 5: What is the role of digital infrastructure and data in enabling needed information exchange between ADS and roadside infrastructure?

Work zones will be the most common anomaly in digital maps unless we begin preparing now. Arrow boards, flagger stations, and other active work zones can be equipped to report their location and other pertinent information automatically and in real time. The same could be done for emergency responders and special events. Only by doing so can we hope to prevent crashes like the one reported January 23rd  ( Mercury News ). Safety is the driving force behind this initiative, but it will also reduce drive times, reduce air pollution, and improve the efficiency of our road networks.

Question 9: What variable information or data would ADS benefit from obtaining and how should that data be best obtained?

Work zones are the single most frequent cause of non-recurring congestion. Clearly real-time work zone data should be included. This data must include the precise location of the work zone, when and where lanes are closed and when they are opened up again, where flagging operations are taking place, and any other important features of the traffic control including lane splits, narrow lanes, crossovers, and full closures and detours. Finally delay times should also be included whenever available.

Question 10: What issues do road owners and operators need to consider in terms of infrastructure modifications and traffic operations as they encounter a mixed vehicle fleet during the transition period to a potentially fully automated fleet?

It is estimated that it will take at least 20 years to reach a point where the vast majority of vehicles are highly automated. Until then work zones will be just as dangerous for conventional vehicles as they are now. Don’t scrimp on traffic control devices, signage or pavement markings in the hopes that they won’t be needed.

As for those automated vehicles, most will not be capable of navigating autonomously though an active work zone. Plan to trigger the vehicles to hand over control to the driver well in advance of the work zone. Studies show drivers need a minimum of 8 to 10 seconds to regain situational awareness.

Work zones, incident response, and special events will test these systems more than anything else. Make them a big part of the conversation now to avoid problems in the not too distant future!

Distracted Driving and Work Zones

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We all know that distracted driving is resulting in increased fatalities on our roadways. The National Safety Council reported a 6% increase in fatalities in 2016. According to the National Work Zone Safety Information Clearinghouse, overall roadways fatalities increased 13% from 2013 to 2016. And during that same period, work zone fatalities increased 28%!

We enjoyed a period of dramatic decline in these numbers in the early 2000’s and then in 2013 they suddenly began to climb again. A small part of that change was due to improving economic activity and the increase in vehicle miles traveled that came as a result. But far more is due to other factors and distracted driving certainly tops the list.

The National Safety Council reports that 47% of drivers feel comfortable texting while they are driving. But we know that, in fact, texting while driving often increases reaction times more than driving under the influence.

But the problem is bigger than just that. In a recent article by Dr. Carl Marci, a neuroscientist writing in the January 4th issue of Perspectives magazine (http://www.nielsen.com/us/en/insights/news/2018/perspectives-driving-while-distracted-the-challenges-of-measuring-behavior-in-complex-environments.html), he said that our cars may be contributing to the distracted driving problem as well! This question occurred to him driving home one night so he ran a test using standard bio-metric equipment on a short drive on an unfamiliar road in Boston. The results showed the driver looked at his or her phone 60 times during a ten minute trip! A study by Zendrive reinforces these findings. They found that drivers use their phones for 88% of their trips.

Dr. Marci explains this by examining the way we use our phones outside of our vehicles. Any time we are bored, we look at our phone. Sitting at home in front of the TV, standing on a street corner waiting for a bus, or sitting in slow a meeting at work – we all check our phones when we get bored. And then we are often rewarded for doing so with a response from others. Email and social media have changed the way we act in very profound and far-reaching ways. And that can’t be turned off when we get behind the wheel.

Furthermore, our cars are becoming very comfortable. They resemble our living rooms more every day. Elaborate electronics help guide us to our destination, provide entertainment, and interface with our phones calling and communications applications.

We do use our cars electronics and phones for legitimate reasons while driving. They give us directions to our destination. They warn us of traffic problems along our planned route. They tell us of weather changes that may be important. So our phones & automotive electronics can help us get where we are going more safely. But once we use these for legitimate reasons, we can’t put them down. Or our drive becomes boring or our phone beeps to announce a new text, and we can’t seem to wait until we stop to check those messages.

So, back to work zones. A 28% increase in work zone fatalities cannot be ignored. Distracted driving is a growing and potentially catastrophic trend for work zones. Work zone ITS has always helped to reduce crashes. But this trend in distracted driving makes the use of work zone ITS all the more important. End of queue systems, dynamic merge systems, and variable speed limit systems can all get drivers attention, improve their work zone awareness, and help mitigate the effects of distracted driving. Let’s get ahead of this trend now before it gets any worse.

The Importance of Crash Modification Factors to Work Zone ITS

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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.