As weather events become more extreme, MassDOT and Massachusetts communities, especially those on the coast, recognize their infrastructure is vulnerable. Coastal cities and towns are currently grappling with the extreme climate impacts of higher temperatures, increased extreme precipitation and greater amounts of sea level rise. All of these impacts are not new, they have slowly been occurring over the past century. It is predicted these changes will accelerate and increases will happen over a shorter length of time (e.g. by 2030, the sea level could rise by 4”-8” (BRAG Report, 2016)).
MassDOT and Climate Ready Boston presented at the April 2018 MassDOT Innovation and Mobility Exchange on the impacts to transportation assets and infrastructure, and strategies to better accommodate climate change. Mia Mansfield, Climate Ready Boston, presented on goals to guide Boston’s future growth:
Goal 1: Provide quality of life in accessible neighborhoods
Goal 2: Drive inclusive economic growth
Goal 3: Promote a healthy environment and adapt to climate change, and
Goal 4: Invest in infrastructure, open space and culture
Associated with these goals are planning and implementation projects for creating resilient infrastructure and buildings, preparing communities, and protecting shorelines. The feedback from the public outreach on what types of flood ready improvements the public would like to see included expanding open space, berm development, and flood walls. Project areas Climate Ready Boston has focused on are East Boston, Charlestown, and South Boston. Mansfield spoke about this initiative saying, “The resiliency strategy embraces layered flood control and integrated green infrastructure measures that mitigate the effects of climate change, and create social, environmental, and economic benefits and value to the people of East Boston and Charlestown and to all who share in the health of the city and the harbor.”
The existing transportation assets will be impacted by more flash floods, landslides, and flooding. Further, increased precipitation could have adverse impacts on the infrastructure that helps move the water, especially on culverts. Hongyan Oliver, MassDOT Office of Transportation Planning, and Chris Dorney, WSP USA, presented on MassDOT’s multi-year statewide Climate Adaptation Vulnerability Assessment study. This study aims first to identify a prioritized set of MassDOT transportation assets throughout the Commonwealth that is at high risk for future inland flooding, and second to provide actionable scientific information for adaptive strategies, and future capital and project planning. This second goal begins on a broader planning level and then is developed through a detailed analysis of vulnerable assets. One challenge is mapping statewide future floodplains where vulnerable assets are located. With this challenge in mind, MassDOT is currently conducting a pilot mapping study on a watershed in western Massachusetts. The approach is to prepare georeferenced data, assign slopes, calculate current peak flows and 100-year flows, elevations, and floodplains, and evaluate the asset exposure. Procedures for floodplain mapping will include developing an instruction manual, applying the data management protocol, and automating parts of the process for efficiency.
Next steps after that will include training additional MassDOT staff on the procedures, and applying the pilot study procedures and lessons learned from all other watersheds in the state and sharing the results and data with stakeholders. Eventually, this important information and these strategies can then be incorporated into MassDOT’s project prioritization, capital planning, asset management system, and emergency preparedness procedures.
May 2018: A car driven with Tesla’s Autopilot driver assist system crashed into a parked police car. The Autopilot system is designed to be used on limited access highways, not on roadways such as this one. (Source: Uncredited/AP/Rex/Shutterstock)
In March 2018, an Uber Volvo operating in automated driving mode, with a driver at the wheel, hit and killed a pedestrian in Arizona. It was the first autonomous vehicle (AV)-related pedestrian fatality. There have been other crashes involving autonomous test vehicles and additional fatalities involving lower-level automated vehicles since. Also in March, a driver in California was killed when his Tesla, in autopilot mode, crashed into a concrete highway lane divider and caught fire. Last month, a Tesla, in autopilot mode, crashed into a parked firetruck in Utah and into a parked police car in California. Injuries were minor in these instances.
All of these crashes have occurred while there has been a driver at the wheel making decisions about when to use and disengage the automated driving assist system. As reported in a USA Today article, following the Utah firetruck crash, Tesla issued a statement saying, “When using Autopilot, drivers are continuously reminded of their responsibility to keep their hands on the wheel and maintain control of the vehicle at all time,” and, “Autopilot is designed for use on highways that have a center divider and clear lane markings.” These conditions are not always met when crashes occur; for example, the driver in the Utah crash admitted to being distracted by their phone before the crash. From the National Transportation Safety Board’s preliminary findings from investigating the Uber pedestrian crash, there was no warning given to the safety driver before the crash. Current AV technologies, such as Tesla’s Autopilot, are referred to by car manufacturers as “driver assistance systems” but it is not clear that all drivers understand their limitations, including the need for drivers to monitor the driving environment and stay involved in the driving process.
The Society of Automotive Engineers has developed a classification system for autonomous vehicles. The classification includes six levels (Level 0-5); with Level 5 being fully autonomous and Level 1, containing some automated features such as adaptive cruise control and parking assist. Most current automated driver assistance systems are Level 1 or 2, meaning that drivers still need to be actively involved.
Driver assistance systems and autonomous vehicles hold great promise for improving safety and mobility, but AV technologies are still relatively new, and numerous challenges remain. A number of universities and researchers in Massachusetts are exploring this topic. In April, a commentary by MIT AgeLab researchers, “People must retain control of autonomous vehicles,” was published in Nature magazine (link is for the article). In their remarks, Dr. Ashley Nune, Dr. Bryan Reimer, and Dr. Joseph Coughlin, Age Lab Director and UMass Transportation Center Research (UMTC) Affiliate, focused on two areas – safety and liability – that need urgent attention as policies and regulations are developed for autonomous and semi-autonomous vehicles. They write that, in their view, “some form of human intervention will always be required. Driverless cars should be treated much like aircraft, in which the involvement of people is required despite such systems being highly automated. Current testing of autonomous vehicles abides by this principle. Safety drivers are present, even though developers and regulators talk of full automation.” The researchers’ piece ends with key points for policymakers preparing AV legislation to consider:
Driverless does not, and should not, mean without a human operator
More information should be shared with operators/drivers about how well different autonomous and driver assist systems are working, including their reliability and limitations
Operators should need to demonstrate that they understand the autonomous and driver assist systems in their vehicles and should be tested on their understanding and competence at periodic intervals
Remote monitoring networks should be established and shift time guidelines considered for workers monitoring AVs.
In May, a forum held at Harvard University’s T.H. Chan School of Public Health on “Self-Driving Cars: Pros and Cons for the Public’s Health.” (A recording of this session and a transcript are available at this link.) Dr. Jay Winsten, Associate Dean for Health Communication at Harvard, said there is hope right now around the potential for autonomous and highly automated vehicles to reduce traffic deaths. He also addressed the hype around this: “I think both the media and some of the manufacturers and developers have been going a little too far in setting public expectations for what to expect, especially in the short-term and in the medium-term.” The panelists discussed that initially most vehicles will be highly automated (SAE Level 2), not autonomous (Level 3-5), and the deployment of the autonomous vehicles is likely to occur first for long-distance, highway-based commercial transport and in urban areas for shuttles and other short-distance trips. There are some challenges including the current reliability and drivers’ understanding of AV technologies, including the need for drivers to stay alert while behind the wheel and the safety of vulnerable road users. There are also concerns regarding regulation. The federal government through the National Highway Safety Administration has developed some guidelines regarding autonomous vehicles and automated driving systems. However, there are currently no federal regulations in place regarding autonomous vehicles. Therefore, currently regulations are primarily set at the state level.
As described in an earlier Innovative Outlook article, Governor Baker and Massachusetts state officials have largely taken the approach that it is better not to regulate AVs through legislation, as the technologies are still evolving and legislation can be difficult to modify once passed. Panelist Deborah Hersman of the National Safety Council, shared those concerns, saying “We’ve got to find out how to do this differently” so that any regulations keep up with changing technology. Herman also urged there be more transparency and data sharing regarding specific AV technologies and how well they perform, saying that NTSB investigations after a crash can be challenged by lack of access to such data.
In June 2018, MassDOT entered into a Memorandum of Understanding with several municipalities to help facilitate and expand autonomous vehicle testing on roadways in Massachusetts. As described in a MassDOT blog article, “Following the signing of this MOU, MassDOT and the participating communities will finalize a universal application for companies to use when seeking to test autonomous vehicles and the participating municipalities will identify locations and roadways suitable for autonomous vehicle testing. ‘This agreement will allow companies to responsibly develop and test autonomous vehicle technology in Massachusetts, while ensuring there are uniform safety guidelines in place,’ said Governor Baker [at the MOU signing] . ‘The MOU builds on the existing autonomous vehicle testing framework while simplifying the process for municipalities to work with innovative companies that are seeking to advance transportation, create jobs in our nation leading innovation economy, and improve our quality of life in the Commonwealth.’ …Said Lieutenant Governor Karyn Polito, ‘By creating a standardized process and working collectively with local officials, we can generate economic growth and support our communities as they play a role in the future of innovation and motor vehicle automation.’ Fourteen communities signed the MOU initially, including Boston, Worcester, Arlington, Boston, Braintree, Brookline, Cambridge, Chelse, Medford, Melrose, Newton, Revere, Somerville, Weymouth, Winthrop, and Worcester. In addition, the Massachusetts Department of Conservation and Recreation also joined the MOU, allowing Commonwealth-owned parkways to be available for autonomous vehicle testing.
AAA has estimated that by 2030, there will be more than 60 million people in the U.S. age 65 & over licensed to drive. (Photo source: IIHS.org, credit istock.com/KLH49)
Most people outlive their ability to drive by seven to ten years. This important statistic from the American Automobile Association (AAA) was cited by Michele Ellicks of the Massachusetts Registry of Motor Vehicles (RMV) at the April 2018 MassDOT Innovation and Mobility Exchange, at a session on Safe Driving for Seniors and People with Disabilities.
There were more than 40 million drivers age 65 years and older in the U.S. in 2015, according to the Federal Highway Administration (FHWA). This population is expected to increase significantly in coming decades. AAA has estimated that by 2030, there will be more than 70 million people in the U.S. in this age group with approximately 85-90% of them licensed to drive. In 2016, 18% of all traffic-related fatalities in the U.S. involved people age 65 and older. In Massachusetts, 16% (133) of all traffic fatalities in the state involved people age 65 and older. Over half (54%) of those fatalities were for those age 65 to 74; the other 46% were for those age 75 and older.
Nationally, the fatality rates per 100,000 people are higher for males than females and generally higher for people age 80 and over than for those 65-79 (see chart below). The death rates increase with age because older people have more physically frail and are more likely to die from injury, as found in this study from John Hopkins School of Medicine. Older drivers are also more likely to be involved in at-fault crashes as a result of physical or cognitive impairments. The fatality rates for females fall slightly from age 80-84 to age 85 and older because females limit or cease their driving in their upper 80s more often than males.
Intersections can be especially difficult for older drivers to navigate. Extensive research conducted at the University of Massachusetts Amherst on driving simulators and on-road has shown that older drivers do not look as often as other drivers towards their turning direction or other vehicles when turning at T-intersections or four-way intersections. As a result, older drivers may be more likely to be involved in traffic crashes.
UMass Amherst researchers working under the supervision of Dr. Michael Knodler are currently investigating older drivers’ crashes during left-turns at signalized intersections; using data gathered from their vehicles and the drivers themselves as part of the SHRP2 (Strategic Highway Research Program 2) project to collect naturalistic driving data on over 2,300 drivers at six cities around the country. The researchers hope this study will help with understanding why and how left turns across path crashes at intersections are more likely for older drivers.
In previous older driver research conducted at UMass Amherst, Dr. Matthew Romoser conducted one study on drivers age 72 to 87 and a comparison group of drivers age 25 to 55 for his dissertation, and then a follow-up study with the older drivers as a post-doctoral researcher. Romoser’s first study, conducted with his advisor, Dr. Donald Fisher, UMass Transportation Center (UMTC) Research Affiliate and UMass Amherst Human Performance Laboratory (HPL) Director, found that the older drivers took fewer roadway glances towards potential hazards than younger drivers while turning. Romoser also found that providing active training and customized feedback regarding their driving to the older participants led to significant improvements in their glances both in a driving simulator and on-road, towards potential hazards as they approached and went through intersections. Romoser’s follow-up study, conducted two years after the first study with the same older drivers, found that those drivers who received active training in the first study still made 50% more glances towards potential hazards than they did before training two years earlier.
The benefits of training programs to help older drivers stay safe at intersections was further examined in a study by past HPL researchers Dr. Siby Samuel and Dr. Yusuke Yamani, with Dr. Fisher. This research found that training programs, such as Dr. Romoser’s, which help improve older drivers’ glance behaviors at intersections, can be effective even though they don’t address underlying declines in cognitive, visual, and motor functions for these drivers as they age. The researchers found some evidence that these training programs are effective because, through the training, drivers learn to decouple their hand, foot, and head movements at intersections, and that doing so may help reduce the impacts of cognitive, motor, and visual declines on their driving.
This research is promising and suggests that some types of training may help older adults safely continue to drive longer than they would be able to otherwise. In Massachusetts, various measures have been taken to promote older driver safety. Under state law, for drivers age 75 and over driver license renewals must be done in person and they include an eye exam. The RMV holds free workshops around the state on issues facing older drivers, including if and when an older person should give up driving.
For adults who do stop driving for safety reasons, MassMobility is a state initiative to improve the transportation options for adults who don’t have a car. The options include both traditional transportation providers such as buses and paratransit and also newer alternatives such as Uber, Lyft, and other Transportation Network Companies (TNCs). A number of sessions at this year’s Innovative and Mobility Exchange discussed alternatives for meeting transportation needs for this population. Options included using TNCs to provide rides outside of regular bus service hours and TNCs partnering with senior centers and other agencies to offer rides to people who otherwise might not be able to access (because they don’t have a smartphone or credit card) services from companies such as Uber and Lyft.
by Tracy Zafian, Research Fellow, and Courtney Murtagh, UMTC Intern
Bicycle in Roundabout (Source: bikewalkencinitas.org)
Roundabouts were introduced to America’s traffic system as a way to increase traffic safety and support greater traffic volumes without extensive new construction. A roundabout’s circular formation works by making incoming vehicles yield to circulating and exiting traffic. This allows cars to maintain a steady traffic flow through the intersection and not have to come to a complete stop. Roundabouts have been proven to be able to handle up to 50 percent more traffic compared to traditional intersections that use traffic signals or stop signs. Further, due to vehicles’ reduced speeds at roundabouts, crash and injury rates can significantly decrease, especially for motorists. According to the Insurance Institute on Highway Safety (IIHS), studies of U.S. intersections that have switched from stop signs or traffic signals to roundabouts have found a decrease in all traffic crashes of 35-47% and a reduction of injury crashes of 72-80%. The IIHS importantly notes that the U.S. studies have focused primarily on single-lane roundabouts. When included in research studies, two-lane roundabouts have been shown to have smaller reductions in crashes compared with single-lane roundabouts or even with increases in crashes. Crashes at roundabouts have also involved bicycle and pedestrians. Non-motorized road users, such as bicyclists and pedestrians, can face several safety and technical challenges when traveling through roundabouts. These challenges can lead to greater crash risk at roundabouts. Dr. Eleni Christofa, UMTC Affiliate Researcher Civil Engineering and Professor Aura Ganz of Electric and Computer Engineering from UMass Amherst are studying the safety of visually impaired pedestrians at roundabouts. Visually impaired pedestrians may be used to having auditory cues from traffic and signals at intersections to know when it’s safe to cross. Roundabouts, designed with continuous traffic flow in mind, may not have such cues. Additionally, it can be difficult for drivers to detect pedestrians at a crosswalk while the driver is focused on navigating a roundabout. Dr. Christofa and Dr. Ganz have developed a new dynamic warning sign to alert drivers entering a roundabout as to where pedestrians are attempting to cross. This sign contains a symbolic traffic circle and symbolic crosswalks for each approach of the roundabout. If a pedestrian is about to cross one of the roundabout’s approaches, they can activate the sign which will then flash to alert drivers where pedestrians are crossing in the roundabout. This is designed to help both with driver awareness of pedestrians and pedestrian safety. The dynamic warning sign will be tested on the UMass Amherst advanced driving simulator this summer. If the sign works as expected, it could be used to help with the safety of pedestrians at roundabouts generally and particularly for the visually impaired and those with mobility impairments who take longer in crosswalks.
Proposed dynamic warning sign for pedestrian crossings at roundabouts. Pedestrians activate the sign to flash and show where they are crossing to help alert drivers traversing the roundabout to their presence.
One of Dr. Christofa’ s graduate students, Derek Roach, conducted other research on roundabouts for his Master’s thesis. His study looked at the impact of roundabouts from a driver behavior, vehicle emissions, and safety perspective. As part of his research, Roach reviewed other studies that examined the safety of bicyclists and pedestrians at roundabouts. One of these studies found that drivers who are exiting a roundabout are less likely to yield to pedestrians than when the drivers enter the roundabout. This same study found that as speed increases in roundabouts, drivers are less likely to yield for pedestrians, making it harder and less safe for pedestrians to cross.
In terms of bicyclist safety, Roach examined a number of studies by researcher Stijn Daniels and colleagues in Belgium. Daniels’ work has found increases in the number of bicyclist crashes and in crash severity when intersections are replaced with roundabouts. Other studies have reported potential explanations for these increases. One study, by researcher Bob Cumming in Australia, found that a contributing factor of bicyclist crashes in one lane roundabouts was bicyclists staying very close to the right curb while going through the roundabout, which would lead motorists to try and pass them in the roundabout. In these cases, it is safer for bicyclists to take the main travel lane instead of being so close to the curb.
At the MassDOT’s 2017 Innovation and Tech Transfer Exchange, presenters from Kittelson and Associates gave an overview on bicycles at roundabouts, including a review of bicycle facility design standards and practices in Massachusetts and elsewhere. Each of the MassDOT Highway Districts in the state has at least one roundabout. MassDOT’s guidance for roundabouts gives special attention to rotary retrofits, building roundabouts in constrained environments, and incorporating state-of-the-practice bicycle and pedestrian design into roundabouts. One important current practice is to treat low-traffic volume and high-traffic volume roundabouts differently, to support bicyclist safety. For lower traffic roundabouts, bicycles are encouraged to circulate with motor vehicles. For higher traffic roundabouts, it is encouraged for bicycles to have a protected intersection with a separate bicycle path, and for bicyclists to have the option of either going through the intersection as a vehicle or pedestrian.
The study’s primary goal was to monitor roadway projects in the Commonwealth that used different experimental mixtures of asphalt to see which mixtures worked best, with the longest service life, best distress resistance, and easiest placement or construction. As described in the study report, the data gathered through this study can aid “Massachusetts in determining if full-scale implementation of these design methodologies and technologies is cost-effective in the long term. Overall, it is anticipated that well-performing technologies could be separated from poor-performing ones, thus leading to better decisions for future infrastructure.”
This study, conducted over a 5-year period (2012-2017), evaluated the performance of experimental hot mix asphalt (HMA) mixtures used in 12 different road pavement projects around Massachusetts. The 12 projects selected by MassDOT staff for this evaluation each involved new pavement technologies or new specifications. These technologies and specifications were tried for a variety of reasons, ranging from trying to mitigate reflective cracks in HMA layers placed over plain concrete slabs to the construction of environmentally friendly “green roads” by the incorporation of warm mix asphalt and ground tire rubber.
As described in the report, at the start of the study the researchers worked to collect all available data from MassDOT on each of the selected projects, including “all bid contract documents, material specifications, plant reports, construction quality assurance data, ride quality and distress data.”
The study then involved developing monitoring plans for each selected project, some of which had been constructed prior to the study. For each site, condition data were collected periodically throughout the duration of the study to quantify the performance of each mix and the changes in performance over time. Data were collected in the same manner for each project, using standardized techniques from MassDOT’s Pavement Management Section, such as surveying distress and calculating the relevant Pavement Condition Index (PCI). This ensured fair and consistent measurements and evaluations for each site.
The study’s primary conclusions and recommendations were as follows:
The condition data provided by the MassDOT Pavement Management Section provided critical data required to be able to evaluate the performance of monitored projects over an extended period of time.
The tested alternative technologies and specifications generally provided acceptable performance in terms of rutting, cracking and ride quality. If the projects continue to display acceptable levels of performance over time, it was suggested that final specifications be developed so that that same mixtures and strategies can be used in the future.
For future road paving projects involving new technologies, it was recommended that a monitoring plan be developed and implemented before the start of these projects. This would allow for a more comprehensive collection of data regarding the technologies’ performance and cost-benefit results over time and assist MassDOT in making more informed decisions when developing project specifications.
The final study report by Dr. Mogawer and Mr. Austerman can be viewed at this link. This research was funded through the MassDOT Research Program with Federal Highway Administration (FHWA) State Planning and Research (SPR) funds.
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