Safe Driving Liquid Solutions for Winter Roadway Maintenance

by Matt Mann, Research Program Coordinator

salt-brine

A major goal of winter maintenance is keeping the rods free from ice/snow.  There is pre-storm preparation and then there is maintaining the roads, in safe conditions, during and after a weather event.  The factors that agencies take into consideration when trying to achieve this goal range from available staff, application rates anti-ice and de-ice material, temperature, and impact on fleet etc.  Among the various solutions, generally, salt is used during a weather event, based on its effective de-icing capabilities; also, it’s easy to handle, store and apply.  Some negative qualities of road salt include: its effectiveness decreases dramatically at 15 degrees and less, it is highly corrosive, it does not stay on the road as much, and it can be costly.

Along with road salt, other winter road products include a number of liquid solutions and/or treated salt.  Some liquid solutions and their qualities include:

  • Calcium Chloride (CaCl) – highly corrosive, freezes at -15 degrees
  • Magnesium Chloride (MgCl) – less corrosive (safe around plants/animals), freezes at -20 degrees
  • “Ice Be Gone”/Magic Minus Zero – non-corrosive, freezes at -40 degrees and is EPA approved
  • Caliper M-1000 & 2000 – non-corrosive, freezes at -85 degrees, good for pre-wet

Another alternative for regular road salt is to treat it.  Some options for treated salt are Magic Salt, Fire Road and Clear Lane.   All of these are less corrosive than regular salt.  Also, when salt is treated, up to 90% stays on the road; where-as un-treated salt, only 60% stays on the road.

Most of the liquids mentioned above can also be used on gravel roads as dust control as well; this adds additional stabilization for the road and prevents loss of gravel over the years.  The costs of these liquids solutions range from MgCl being the cheapest to “Ice Be Gone” being the more expensive one.  In the middle is Caliper M-100 and M-2000.

Currently MassDOT pre-treats the state highways with a salt brine, and pre-wets their roads with MgCl.  They are able to get a jump on most weather events by using pavement temperatures sensors and the Roadway Weather Information Stations (RWIS).  Speaking with Paul Brown, District 1, MassDOT, “Most new trucks are equipped with pavement temperature sensors.”  MassDOT also fully utilizes the RWIS, which measure real-time atmospheric parameters, pavement conditions, water level conditions, and visibility.

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The Latest Transportation Tools Update from ITE and FHWA

By Courtney Murtagh, UMTC Research staff

This past fall, both the Institute of Transportation Engineers (ITE) and the Federal Highway Administration, made important updates to their transportation research tools.

The ITE released the 10th edition Trip Generation Manual, which consists of two volumes: volume one- Desk reference and volume two- Land use data plots. It also comes with the third edition trip generation handbook, and a new web-based application titled ITETripGen.

The updated manual provides a detailed description of both vehicle and person-based trip generation data for all different settings including urban, suburban, and rural areas. The data set of land use description and plots for all land use/time period/independent variable combinations has been updated with twenty-two new land use classification for more than 1,700 sites.  The new desktop app allows users to access the entire trip generation data-set electronically, with plenty of filtering options including site setting, geographic location, age of data, development size, and trip type.

The Federal Highway Administration updated their Interactive Highway Safety Design Model (IHSDM),is a software analysis tool used to evaluate highway designs expected safety and performance based on data collected from existing highways.

The tool now includes an economic analysis option (EA Tool). The purpose of the new EA tool is to allow project managers, highway designers, and others using the tool to estimate the cost of crashes predicted for one or more designs and run benefit-cost analyses. Data has also been updated on the app, which now includes a lane offset option for urban and suburban arterials. Minor graphical user interface, output/reporting, documentation, and system administration tools were updated to adapt to the new EA Tool.

Both these changes are significant to improve safety in highway designs, and improved modeling and design for transportation engineers.

 

Safety in the Zone: the Work Zone

by Tracy Zafian, UMTC Research Fellow

On the evening of September 30, 2017, a road construction worker in Ohio, Steve Cook, age 59, was hit and killed by an impaired driver while in a work zone. Just before the crash, the driver looked down at his cell phone. Not only distracted, the driver had also been drinking. He now faces charges of vehicular manslaughter.

WorkZonePic2_source_Wayne_State_University
Source: Wayne State University

Roadway work zones can be hazardous both for drivers and for workers on site. The latest data from the Federal Highway Administration show that in 2015 nationwide, there were an estimated 96,626 crashes in work zones an increase of 8% over 2014. Of these crashes, 642 (0.7%) involved at least one fatality.

On average, 85% of work zone fatalities are drivers or passengers in cars. Of the fatal crashes in 2014, major contributing factors included speeding (28%), lack of seatbelt use (25%), alcohol (25%), and distraction (16%). Approximately 40% of fatal crashes in work zones are rear-end collisions. When compared to 16% of all fatal crashes nationwide, this is a huge percentage. It also provides insight into areas for improvement.

States have approached this issue a few different ways. Some have focused on safety campaigns, others on enforcement and some states have looked into technology to help decrease these crashes. Most safety campaigns encourage drivers to drive more slower and be alert in work zones. Almost all states have increased fines for speeding or other traffic violations in work zones. In Massachusetts and many other states, the fines in work zones are doubled.

Illinois, which has had a general prohibition against handheld cell phone use while driving since 2014, has banned hands-free cell phone use in work zones. Arkansas banned handheld cell phone use while driving in work zones in 2011. Wisconsin is another state specifically banning handheld cellphone use by drivers in construction zones. Wisconsin’s ban took effect in October 2016, and after one year, it isn’t clear it’s having the desired effect. Since the ban started, and combined with increased enforcement, new work zone signage, and a safety campaign, the number of work zone crashes is up and many people are still using their cell phones in work zones. According to David Pabst, Director of Safety for the Wisconsin Department of Transportation, “It’s still a problem, and we haven’t gotten the message through to people to put their phone down in a work zone.”

Massachusetts has been looking at engineering and technology options for improved work zone safety. In June 2016, the Massachusetts Department of Transportation (MassDOT) established a Work Zone Safety Task Force with members from a number of MassDOT divisions, the Massachusetts State Police, the Executive Office of Public Safety and Security, the Massachusetts Sherriffs’ Association and Construction Industries of Massachusetts. The Work Zone Safety Task Force issued recommendations in early 2017 and MassDOT is now in the process of implementing a number of new safety enhancements in work zones, including portable rumble strips at the beginning of work zones, and flashing blue LED lights on portable trailers in work zones, to simulate the presence of a police vehicle. Pilot testing of trailers with these blue lights has been conducted at construction zones along Route 2 and Interstate 190.

There are a number of additional technology options that could be considered moving forward., including using communication technologies. IBM-designed SmartCones use wireless technology to alert construction zone workers to potential threats. SmartCones placed strategically ahead of a work zone have been shown to be effective at alerting drivers about the work area and at slowing traffic.

smart_cone
Each SmartCone contains a high powered computing platform running SmartCone IoT software and sensors. Source:  http://www.thesmartcone.com

Researchers at the University of Transportation Center in Alabama recently evaluated a number of different intrusion sensing and alarm technologies for alerting construction zone workers when a vehicle has errantly entered their active work area. Led by Eric Marks, Ph.D., the research team compared different options including kinematic, infrared, pneumatic, microwave, radar, and radio technologies, and then field tested two commercially-available systems: Intellicone Safelane and the Traffic Guard Worker Alert System. Both systems are portable and easy to deploy around a work site. Both use sensors that detect intrusion and then wirelessly send signals to an alarm system with multiple types of alerts.

In their analysis, the researchers evaluated the systems’ alarm volume, worker response time, driver response time, and vehicle stopping time and distance at different traveling speeds. The Intellicone and Traffic Guard systems performed comparably, and on average it took a worker less than 1 second to respond to the warning alerts. Based on their review and analysis, the research team recommended the Traffic Guard system for short tapers in work zones and for short-term or mobile highway construction zone projects. The Intellicone was recommended for longer tapers where traffic barrels or other longer-term temporary devices are being used. The researchers recommended the AWARE (Advanced Warning and Risk Evasion) system for safety against intrusion in longer-term work zone projects. AWARE requires the most infrastructure and setup, but provides the most comprehensive alarms.

Resource for further information: National Workzone Safety Information Clearinghouse, www.workzonesafety.org.

Distracted Walking: A Global Epidemic

By Courtney Murtagh, Tracy Zafian, and Matt Mann, UMTC Research Staff

Most of us are aware of the dangers of distracted driving, but distracted walking? Around the world and close to home, it’s a growing epidemic. More and more people are texting and using their phones while walking in intersections, creating unsafe situations.

distracted_peds_source_Premier_Insurance_Corp
source: Premier Insurance Corporation

A 2017 report by the Governors Highway Safety Association found that pedestrian roadway deaths in the US are now at their highest level in over 20 years, with more than 6,000 pedestrian fatalities in 2016. An article in the May 2017 MassDOT Innovative Outlook, discussed a number of contributing factors for this, including: more driving; alcohol use by drivers and pedestrians; lack of pedestrian visibility; and driver and pedestrian distractions.

Dr. Cole Fitzpatrick, a UMTC Affiliate Researcher, recently conducted a field study on the prevalence of distracted walking and its effect on driver behavior. The study included observations of a total of 1,386 pedestrian crossings and 890 pedestrian-vehicle interactions at seven different crosswalks on the UMass Amherst campus. The researchers found that nearly half of all pedestrians were distracted while crossing the street, with 22% of them talking to another person beside them, 16% using headphones, and 10% either texting or talking on their phones.

Cities have begun to take notice of distracted walkers and are looking for ways to improve intersection and crosswalk safety. In October 2017, Honolulu enacted a law allowing pedestrians who text on their phones while crossing the street to be fined $15 to $99 for doing so.  This new law is thought to be the first such law of its kind in the country. Prior to October,  Honolulu had more pedestrians being hit  by vehicles in crosswalks, than any other major US City. Local high school students were instrumental in pushing for this law. Kel Hirohata, a local high school teacher interviewed on National Public Radio recently, described how the Youth for Safety club at Waipahu High School spent more than a week watching fellow students as they left school. They noticed an alarming trend: many of their classmates staring at their phones while crossing the street. The Safety club members took note of the potential danger, and then followed up with a local councilmember who wrote a bill which then became the new law.

Legislators in other places have also proposed laws to curb texting while walking. In San Mateo County, California, County board members unanimously voted in favor of a resolution in September 2017 asking state lawmakers to pass a law banning cell phone use in crosswalks. Stamford, Connecticut is now considering an ordinance that would ban cell phone talking or texting while crossing the street and impose a $30 fine for offenders. In September 2017, New York State passed a law requiring the New York City Transportation Department to study and report on its efforts to educate drivers and walkers about the dangers of pedestrians distracted by cell phones.  In Massachusetts a bill was introduced this November to ban texting while jaywalking. No action has yet been taken on this proposed legislation.

It’s not just in the United States that officials are looking into distracted walking. Bodegraven, Amsterdam for example installed lights in the ground near crosswalks that would change colors with the traffic lights, so people looking down on their phones would be more aware of the nearby traffic and when it’s safe to cross.

LED_sidewalk_lights_in_Amsterdam_Lichtlijn-Foto-Gemeente-Bodegraven_source_www_omroepwest_nl
LED sidewalk lights in Amsterdam. Source: http://www.omroepwest.nl

 

Live from NYC-Times Square – UMass Raises Awareness about Texting and Driving

NYCText
Source: University of Masaschusetts-Amherst

By Melissa Paciulli, Manager of Research, and Tracy Zafian, Research Fellow 

UMass at Time Square! A billboard designed by UMass-Amherst students to raise awareness of the dangers of texting while driving is currently being displayed in Times Square in New York. The billboard will also be displayed on Route 9, Interstate 495 near Lawrence and Methuen and I-290 in Worcester, Massachusetts. Other locations around the country will also display the sign.

The billboard was created with the help of the UMass Adlab at the Isenberg School of Management at UMass-Amherst, under the guidance of Isenberg professor Elizabeth Miller by UMass student Kyle Pandiscio (’19) and now graduate Julia Keefe.  At the UMass Adlab, students develop advertisement and campaign images to market “change” for real-life clients.

As described in this UMass press release,  Keefe and Pandiscio won the Project Yellow Light billboard Public Service Annoucement (PSA) competition with a billboard design autocorrecting “Don’t Text and Drive” to “Don’t Text and Die” to enforce the concept that a texting accident can occur in a split second. Their billboard design was selected from 1,150 entries.  Pandiscio and Keefe realized the irony of creating a billboard when the campaign’s whole point is for drivers to keep their eyes on the road, so they maximized the impact by making the format the text message itself. “When people are driving, the last thing [we] want to do is create a billboard that is distracting,” Pandiscio told the Boston Globe.

The Project Yellow Light competition was sponsored by the Ad Council, the U.S. Department of Transportation’s National Highway Safety Administration, the National Organizations for Youth Safety, U-Haul, Mazda, Clear Channel, and I Heart Radio.  The contest included categories for video, radio and billboard PSAs, with entries submitted by high school and college students.

B.U.B.S. – Buckling Up in the Back Seat!

backseat
Only 51% of high school students report always wearing a seatbelt while riding in a car.            Photo Source: Manitoba Public Insurance, https://www.mpi.mb.ca

By Tracy Zafian, Research Fellow

According to a recent nationwide study, adults are less likely to use a seatbelt when sitting in the backseat of a vehicle than the front seat. The survey, conducted by the non-profit Insurance Institute for Highway Safety, (IIHS) found this was especially true for adults taking taxis or services such as Uber or Lyft. Among people who make most of their car trips as a rear-seat passenger in such vehicles, only 57% reported always using their seatbelts. In comparison, 74% of the survey respondents overall said they wear seatbelts while in the back seat of personal vehicles.

The survey also found that people ages 35 to 54 were the least likely, (66%), to report always buckling up in the back seat, compared to adults ages 18 to 34 (73%), and those 55 and over (76%). Women were also more likely than men to use seatbelts while in the back seat.

People who buckled up less often while in rear seats were asked why; a quarter of them said they believe the back seat to be safer than the front seat. The survey found that many of those who don’t buckle up in the backseat are more likely to buckle up if they are sitting in the front seat.

Unbelted passengers create a safety risk to themselves and others no matter where they are sitting. As described in this NBC news article and video, in a crash, an unbelted rear passenger can still be thrown about the vehicle and could harm both themselves and others. The IIHS reports that drivers are twice as likely to be killed in crashes when a passenger sitting behind them has no seatbelt restraining them.

Crash data from National Highway Safety Traffic Administration (NHTSA) demonstrates the importance of buckling up. According to the Fatality Analysis Reporting System (FARS), close to half (49%) of passenger vehicle occupants killed in U.S. vehicle crashes in 2016 were physically unrestrained during those crashes. This includes more than 50% of the children killed in crashes who were not in seatbelts or car seats, and 58% of people ages 18 to 34 who died in crashes unbelted. The FARS data show 296 fatalities in vehicle crashes in Massachusetts in 2016; almost half of them were found to not be wearing a seat belt (of those where seat belt use could be determined).

Charles Kahane, Ph.D., formerly at the National Highway Transportation Safety Administration (NHTSA), has conducted extensive research on seat belts and safety. He has estimated that wearing a seat belt cuts drivers’ and front-seat passengers’ risk of fatal injury by 45% in passenger cars and up to 60% in SUVs, vans, and pickup trucks. In an analysis of backseat seatbelt use in passenger cars, Mr. Kahane found that buckling up in the center rear seat reduces fatality risk by 58%. For side rear seats, seatbelt use reduces fatality risks by 54%.

Seat belt laws and enforcement help encourage greater seatbelt use.  Every U.S. state except New Hampshire has a law requiring seat belt use (Details on the laws for each state here). Thirty-four states and the District of Columbia have primary seat belt laws that allow police officers to stop vehicles solely because of a seat belt violation. Seat belt laws in the remaining fifteen states, including Massachusetts, are enforced secondarily, meaning that police officers must stop a vehicle for another infraction before they can issue a seat belt ticket. Twenty-nine states and DC have laws for back seat seatbelt use, though some of these laws exempt adults or children over a certain age in the back seat from their seatbelt requirements. Massachusetts’ law requires children to have safety seats until they are at least 8 years of age or over 57 inches tall, and that everyone else traveling in a car wear a seatbelt.

The Massachusetts Executive Office of Public Safety and Security (EOPSS) runs public education and enforcement campaigns, such as Click it or Ticket, to encourage greater seatbelt use. EOPSS also funds an annual month-long observational study on seatbelt usage. The study counts on the number of drivers and front seat passengers wearing and not wearing seatbelts. The information is collected at various roadway locations around the Commonwealth. UMTC Post-Doc Researcher Cole Fitzpatrick and UMassSafe Associate Director Robin Riessman oversaw the 2017 study. The 2016 seat belt study results are on the EOPSS web site. In Massachusetts from 2006 to 2016, the observed safety belt usage rate for front seat occupants increased from 67% to 78%. The 2017 results are not posted but the prepared report shows a slight decrease in front occupant safety belt usage to 74%.

The same type of data collection is done on a national level each year through NHTSA’s National Occupant Protection Use Survey. The 2016 results showed that nationally, seat belt use by front seat occupants reached 90%, including 92% in primary seat belt law states and 83% in other law states.

One approach Massachusetts and the 14 other states could take to promote greater seatbelt use is to change seatbelt laws from secondary to primary, which allows stops for seat belt enforcement. However, another approach could be technology in cars to provide warnings and reminders to vehicle occupants, especially backseat passengers, to wear their seatbelts.  Most modern cars provide warnings (red seatbelt lights on the dashboard, for example) to remind drivers to buckle up in the car. As IIHS discusses, however, no US-made cars currently have similar warnings to remind backseat passengers of this.  Such warnings and reminders could be implemented for taxis and ride-sharing services too; to help the increasing numbers of backseat passengers to stay safe!

Autonomous Vehicle Research: MassDOT Leads the Way

by Tracy Zafian, UMTC Research Fellow

More U.S. states are considering legislation and regulations for highly automated vehicles (HAVs) testing. Twenty-four states and the District of Columbia have now enacted legislation regarding the testing of highly autonomous vehicles. Only Michigan currently allows the driverless HAVs on public roads; California is considering the same but has not approved it yet.

The federal policy (Federal Automated Vehicles Policy) provides guidance for those developing, testing, and deploying highly automated vehicles. The policy considers current and potential regulatory tools that could be used with these vehicles. The policy also describes the different responsibilities on the federal and state levels, and creates a model for state policy that recommends policy areas for states to consider for automated vehicles.

Figure 1: States with Enacted Legislation for Autonomous Vehicles

IOpicAs of July 27, 2017. Source: National Conference of State Legislatures. http://www.ncsl.org/research/transportation/autonomous-vehicles-self-driving-vehicles-enacted-legislation.aspx

In October 2016, Massachusetts Gov. Charlie Baker signed Executive Order No. 572, To Promote the Testing and Deployment of Highly Automated Driving Technologies (EO 572). EO 572 created a state government working group on autonomous vehicles (AV Working Group). The group’s charge is to “convene and consult with experts on motor vehicle safety and vehicle automation…and [to] work with the Legislature on any proposed legislation necessary to protect the public welfare.” The AV Working Group is led by Katherine Fichter, Massachusetts Department of Transportation (MassDOT) Assistant Secretary for Policy Coordination and Transportation Secretary Stephanie Pollack’s designee to the group. The AV Working Group also includes other MassDOT staff and representatives from the State Police, the Executive Office of Public Safety and Security, Housing and Economic Development, and the State Legislature.

One Center, at the UMass Transportation Center, has recently contracted with UMTC Research Affiliates, at UMass Lowell, to conduct research on the technological developments, regulatory requirements, funding opportunities, and potential benefits of the emerging AV technology to take appropriate actions for the benefit of the citizens of the Commonwealth. The affiliates associated with this research are Chronis Stamatiadis, Nathan Gartner, Yuanchang Xie, and Danjue Chen. This project will provide baseline information pertaining to strategic planning for connected vehicle (CV) technologies. This information will be used by MassDOT to develop a strategic plan for the development and deployment of connected vehicle technology and infrastructure in Massachusetts.

EO 572 authorized MassDOT, with input from the AV Working Group and other technical experts, to develop and issue guidance for testing highly automated vehicles on public roadways in Massachusetts, and includes a process for companies to obtain approval for such testing.

Highly automated vehicle testing on public roadways is under the authority of MassDOT. Presently in Massachusetts, most testing takes place in spaces and courses outside of MassDOT’s jurisdiction, such as universities, private indoor testing facilities, and the former Fort Devens military base.

As described by Boston National Public Radio station WBUR, nuTonomy, a Massachusetts Institute of Technology (MIT) spinoff company, began the first testing of highly automated cars on Boston roads in January 2017. The initial testing area was limited to a 191-acre industrial park in South Boston, the Raymond L. Flynn Marine Park, which has a simple road layout, no traffic signals, and only 3 miles of roadway. At first, testing was approved only for daylight hours and good weather, but then was expanded to nighttime and inclement weather. The company has now logged over 200 miles of automated vehicle driving in the industrial park, with no crashes or incidences. With these results, in April 2017, nuTonomy was granted approval to expand its HAV testing to the Seaport and Fort Point areas. A Boston Globe article discussed this approval and interviewed City of Boston and nuTonomy staff. The Seaport roadways are considerably more complex than the testing roads so far, including more complicated intersections, traffic signals, roadways with multiple lanes, bridges, and a rotary. As before, nuTonomy’s testing in the expanded area initially was for daylight hours and good weather only.

In June 2017, MassDOT granted permission for a second MIT-spinoff company, Optimus Ride, to test highly automated vehicles on Boston roads. As described in a Boston Globe article, Optimus Ride will initially test its vehicles only in the Raymond L. Flynn Marine Park, as nuTonomy did.

During their HAV roadway testing, nuTonomy and Optimus Ride both have a human operator sitting in the driver’s seat, ready to take over control of the vehicle if needed. This is currently standard for most on-road testing of HAVs. Some companies use two human workers, one in the driver seat and one in the front passenger seat, to help sustain vigilance and monitoring of the HAV’s driving and the ability to switch to manual driving mode if ever needed. As described in its road test application to MassDOT, after 200 miles of testing, Optimus Ride may request MassDOT permission to test its vehicles with passengers.

In terms of legislation and regulations for automated vehicles (AVs), in her keynote talk at a recent conference on Autonomous and Connected Vehicles held at Worcester Polytechnic Institute, Ms. Fichter indicated that Gov. Baker and MassDOT have taken the position that it is better not to regulate AVs through legislation. AV and HAV technologies are still evolving, and legislation can be difficult to modify once passed. In the Massachusetts Legislature, there are currently eight bills that have been filed related to AVs. On July 13, 2017, the AV Working Group held a legislative meeting to discuss them and hear more about them from their proponents. The MassRobotics Consortium has posted its notes from the meeting. Most of the bills include guidance for AV safety and for liability in the event of a crash involving an AV, with no liability assigned to the original manufacturer of a vehicle that has been later converted to an AV. Joint bills S. 1945/H. 1829 also request that all AVs be zero emission vehicles (ZEVs), encourage AVs to be for public transit only in areas with dense populations, provide guidance for AV data collection, and propose having a vehicle-miles-traveled (VMT) tax on AVs. The idea of a VMT-based tax raised questions and issues at the meeting, related to such issues as geographic equity, fuel consumption and encouraging efficient vehicles, and collection of vehicle owners’ travel data, as well as the need for additional revenues as more vehicles are converted to AVs and electric vehicles.

Among the other proposed AV legislation, H. 2742 requires that AVs used for the interstate transport of goods or for transporting eight or more people be required to have a human operator present who can intervene if needed. Bills S. 1938 and H. 3422 both focus on making AVs that do not require a human operator available to the public. Bills H. 1822 and H. 1897 each request that MassDOT submit a report to the state House and Senate leaders “recommending additional legislative or regulatory action that may be required for the safe testing and operation of motor vehicles equipped with autonomous technology.” H. 1897 requests such a report by June 2017, while H. 1822 requests it by March 2019.

At the end of the July AV Working Group meeting, Ms. Fichter recommended the next meeting would be in September 2017. At this meeting, people from the AV industry will present and provide their perspectives regarding AVs and HAV regulation, and how AV technologies will come to market.

 

 

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UMTC Affiliates & MassDOT Assistant Secretary Katherine Fichter Present at WPI Conference on Vehicle Automation

By Tracy Zafian, UMTC Research Fellow

In May 2017, Worcester Polytechnic Institute (WPI) held its second annual Connected and Autonomous Vehicles Summer School speaker series, sponsored by the Institute of Electrical and Electronics Engineers Vehicular Technology Society (IEEE VTS). The event included two days of lectures and discussions.

CAV intersection
Photo source: U.S. Department of Transportation
  • Danjue Chen, Professor at UMass-Lowell and UMTC Affiliate, discussed the impacts of connected and automated vehicles (CAVs) on traffic operations and highway traffic flow, and how CAVs can help optimize roadway capacity and traffic control. Professor Chen is the featured researcher in this month’s Innovative Outlook (IO).
  • Hossein Pishro-Nik, Professor at UMass-Amherst and UMTC Affiliate, spoke about Vehicular Ad Hoc Networks (VANETs) for vehicle-to-vehicle and vehicle-roadway infrastructure communications. His talk discussed the relationship between communications and safety in VANETs, how VANETs can be customized for different traffic conditions and individual drivers, and the issues of privacy in VANETs and Internet-connected devices and applications. Professor Pishro-Nik’s research is described in more detail in another post.
  • Jason Rife, Professor at Tufts University, presented information on different GPS-based technologies and applications that can assist with automated vehicles and navigation, even in dense urban areas with limited sky visibility.
  • Bob Sletten, Engineering Manager at Autoliv, a company that develops automotive safety systems for auto manufacturers, spoke about radar technology in automotive applications.
  • Akshay Rajhans, Senior Research Scientist at MathWorks, spoke about model-based design for connected autonomous vehicles. As described in the WPI conference program, “model-based design makes use of computational models of systems under design that are developed, optimized and checked after correctness specifications throughout the design cycle.”
  • Alexander Wyglinski, WPI Professor and organizer of the conference, provided an overview of vehicular communication systems and the fundamental concepts for understanding, designing, and implementing them.

The keynote speaker at the gathering was Katherine Fichter, Assistant Secretary for Policy Coordination at MassDOT. Ms. Fichter discussed the potential future impacts of driverless vehicles under different scenarios, including a Driverless Utopia and a Driverless Nightmare that were described in Driving Towards Driverless Cars, a blog by Lauren Isaac. Under these scenarios, autonomous vehicles are expected to improve roadway safety, increase vehicle miles traveled, and reduce greenhouse gas emissions, but there are other potential impacts that are less certain. For example, will more driverless cars reduce urban sprawl or increase it, and how will the mobility of low-income people be impacted? As Ms. Fichter discussed, there are questions as well about how autonomous vehicles will be regulated and insured. One big challenge is that current regulations are all based on the idea that vehicles have human operators; this will need to change.

Customizing Your Self-Driving Car

by Hossein Pishro-Nik, University of Massachusetts-Amherst

In the future, intelligent transportation systems (ITSs) will involve connected vehicles, including driver-assisted vehicles and self-driving cars, as well as on-board mobile devices, sensors, and the software and algorithms that govern the functioning of these devices and their communications. Despite recent improvements, each year tens of thousands of lives are lost and billions of dollars are wasted because of traffic inefficiencies in the United States alone. Improvements in the transportation systems could have an enormous impact on lowering these statistics.

In this research, we aim to establish a new approach in design of safety systems, which is based on the individualization and customization of these systems to specific drivers and their environments. This means that wireless communication protocols, as well as algorithms that communicate to users, can be designed in an intelligent way in order to take advantage of all the statistical data that is available regarding the driver and his/her environment.

To accomplish this objective, we can use the technology to collect driver performance data and subsequently learn driver characteristics and driving strategies. This information, along with data collected from other vehicles and roadside units, can be used to customize the technology to each driver. With this, it is possible to adapt warnings or automatic control strategies to each driver. Meanwhile, vehicle-to-vehicle (V2V) communication can be dynamically tuned to make efficient use of finite bandwidth and guarantee the transmission of information critical to safety.

In this way, we should consider that there is an uncertainty of the message delivery between two specific vehicles, while other vehicles might also transmit simultaneously. Our research shows that by proper adaptation of wireless communication and warning algorithms, we can potentially reduce accident fatalities by a considerable amount.

To understand the benefit of V2V communication, consider a traffic stream where a chain of vehicles moves with same speed. When the first vehicle in the chain brakes, the driver of the following vehicle applies the brake after her perception reaction time (PRT). If no intervehicle communications are employed, vehicle Vi applies the brake after the sum of PRTs up to the driver i. With the communications, this time will change to the communications delay plus PRTs of the driver i. This is shown in Figure 1.

Hossein_Fig1new
Figure 1. Communications delay versus sum of PRTs, illustrating the time before a driver in a chain applies the brake

Some drivers may think that some of the received warning messages are not needed, because the drivers are aware of their own response time empirically and they know that they can react to stimuli fast. These warning messages are false alarms for these drivers. These warning messages may frustrate the drivers with an overly high number of false alarms, causing them to ignore warnings or even disable the system. To address this issue, we propose estimating the PRT of drivers and personalizing warning messages based on individual PRTs. Figure 2 shows that at the same accident probability for each driver, the false alarm rate can be reduced by at least 30% by employing the estimated individual distribution instead of the population distribution. Thus, it is of vital importance to minimize false alarms so that the system sends warnings only when they are needed.

Hossein_Fig2new
Figure 2. False alarm rate versus the probability of accident based on using average response time or individual

Now, we should determine how channel access probabilities of vehicles and vehicular communications can be adapted to drivers’ characteristics. In a network of vehicles, each vehicle transmits with a specific probability in the transmission medium. Large channel access probabilities lead the system to excessive interferences and, consequently, low probability of packets being successfully received (success probability), while very small values reduce the success probabilities since the probability of the favorite transmission is low itself. Therefore, there is an optimal value, given both the physical data obtained by vehicular networks and the communications protocol requirements, which results in lower collision probability of vehicles. We can find the expression of packet success probability in a network of vehicles based on channel access probability of vehicle.

We then use a recursive algorithm to tune the transmission probability of each vehicle based on the individual characteristics of drivers. The PRT of the driver, traffic conditions, and communications delay are three factors that play roles in assigning channel access probabilities to vehicles. In simple terms, we categorize the drivers into safe and unsafe drivers based on perception-reaction time. The unsafe vehicles are the ones whose drivers have long perception-reaction time and low distance to the vehicle in front. In other words, unsafe vehicles have higher collision probability. Then we assign different channel access probabilities to unsafe and safe vehicles respectively.

Figure 3(a) illustrates the collision probabilities when channel access probabilities are assumed to be equal for all vehicles. Figure 3(b) shows the scenario in which different channel access probabilities are assigned to unsafe and safe vehicles. The minimum collision probability in the second scenario improves by 25%.

Hossein_Fig3a
Figure 3(a). Collision probabilities when channel access probabilities are equal for all vehicles
Hossein_Fig3b
Figure 3(b). Different channel access probabilities are assigned to unsafe and safe vehicles.

Our simulation results confirm that unsafe vehicles need to inform other vehicles of their perilous situation more frequently than do safer vehicles. In other words, with higher channel access probability for unsafe vehicles, we can achieve lower collision probabilities.

Hossein Pishro-Nik is a UMTC Research Affiliate and an Associate Professor in the Department of Electrical and Computer Engineering (ECE) at UMass-Amherst. This research was supported by the National Science Foundation under Grant CCF– 0844725 (PI: Hossein Pishro-Nik). It is a joint work with ECE PhD students Mohammad Nekoui, Ali Rakhshan, and Mohammad Kohsravi, and Professor Daiheng Ni from the UMass-Amherst Department of Civil and Environmental Engineering. For more information and access to published papers, please visit http://www.ecs.umass.edu/ece/pishro/publications.html.

GM Rolling Out AV Fleet

By Tracy Zafian, UMTC Research Fellow

General Motors Company (GM) announced in mid-June that it completed production of 130 self-driving Chevrolet Bolt electric vehicles for testing automated vehicle (AV) technologies on-road. These highly automated vehicles (HAVs) join GM’s more than 50 Chevrolet Bolts with AV technologies already operating on public roads in San Francisco, Detroit, and Scottsdale, Arizona. In April 2017, Spectrum, the flagship magazine for the Institute of Electrical and Electronics Engineers (IEEE), reported on GM plans to have as many as 300 more self-driving vehicles on-road, presumably including the recently completed 130 vehicles. According to Spectrum, GM would then have the largest HAV fleet on-road not only in the United States, but worldwide. Google-based Waymo has the second-largest AV fleet in the United States, with an estimated 160 vehicles on-road.

GM CEO & Chairman Mary Barra with a new Chevrolet Bolt AV (Photo by Paul Sancya, Associated Press)

In GM’s announcement regarding the 130 new self-driving Bolts, GM Chairman and CEO Mary Barra is quoted: “This production milestone brings us one step closer to making our vision of personal mobility a reality …. Expansion of our real-world test fleet will help ensure that our self-driving vehicles meet the same strict standards for safety and quality that we build into all of our vehicles.” CEO Barra has also said that “no other company today has the unique and necessary combination of technology, engineering and manufacturing ability to build autonomous vehicles at scale.”

The new self-driving version of the Chevrolet Bolt is the second generation of GM’s AVs and is capable of handling almost any roadway situation without human driver intervention. The new Bolts are equipped with the latest technologies in cameras, radar (LiDAR), sensors, and related hardware. “There are even a couple of cameras that are dedicated just to seeing traffic lights to make sure you don’t run red lights,” said Kyle Vogt, CEO of Cruise Automation, a self-driving software company that GM acquired in 2016. The GM HAVs always have an employee in the driver’s seat for safety reasons, just in case any intervention is needed. Almost all states with HAV regulations also have the requirement that a human operator be present.

In 2016, GM also partnered with and invested $500 million in ride-sharing company Lyft. In a recent Forbes article, Cruise CEO Vogt wouldn’t confirm a Reuters report that “thousands” of self-driving Chevrolet Bolt hatchbacks will go into service for ride-hailing company Lyft in 2018, but said it wouldn’t be surprising. “We’ve had a plan in place for a while and it’s going according to schedule. From what I can tell it’s much faster and going to happen much sooner than most people in the industry think,” Vogt said. “We’re planning to deploy in a rideshare environment, and very quickly.