Hot Mix Asphalt Mixtures – What Works

by Courtney Murtagh, UMTC Intern, and Tracy Zafian, Research Fellow

wallapic
Road paving project in Lee, MA, 2010. (Source: blog.mass.gov).

Dr. Walaa Mogawer, UMTC Research Affiliate, Professor at UMass-Dartmouth, and UMass-Dartmouth Research Engineer Alexander Austerman recently published the results of their research study on Experimental Hot Mix Asphalt Projects Placed in Massachusetts. Professor Mogawer discussed this research topic in an Innovative Outlook interview in September 2017.

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.

Massachusetts Highlights Alternative Transportation Achievements

by Courtney Murtagh, UMTC Intern

hubway
Hubway bike Sharing Boston

As warm spring temperatures finally welcome us in Massachusetts, pedestrians and bicyclists emerge from a long winter’s hibernation. Lucky for many of these pedestrians and cyclists, they are greeted by new infrastructure, trails, and programs implemented by the Baker-Polito Administration and the City of Boston.

All throughout 2017, the Massachusetts Department of Transportation (MassDOT) worked to improve pedestrian and bicyclist infrastructure to get more people using alternative modes of transportation. In November 2017, their work seemingly paid off, when Massachusetts was nationally recognized by the League of American Bicyclists for being the fourth most bicycle-friendly state in the nation.

The report took into account each state’s infrastructure, funding, policies, programs and education on bicycle friendliness when creating the rankings. It is no wonder Massachusetts ranked so high on the list as huge strides have been made in the past year to fund alternative transportation.

For example, Governor Baker created an Interagency Trail Team with MassDOT, the Executive Office of Energy and Environmental Affairs, and the Department of Conservation and Recreation (DCR). Their goal is to create a unified network of biking trails throughout the Commonwealth.

So far, $1.5 million has been dedicated to fund designs of the 10-mile Northern Strand Community Trail running through Everett, Lynn, Malden, Revere, and Saugus. There has been $12.2 million distributed to 33 municipalities in order to improve over 200 intersections and crosswalks, as well as add or improve over 16 miles of sidewalks and trails.  At least eight other trails or intersections have also been completed, improved, or added this year.  There has been an increase in education for bike safety through videos, conferences, and safety campaigns like, “Scan the Street for Wheels and Feet.”

The Baker-Polito Administration also increased funding to $3.2 million per year for the DCR to give out grants for those who wish to construct or maintain trails across Massachusetts for the next two years.

This summer, as part of this healthy and supporting alternative transportation initiative, Boston’s Hubway, a bike sharing system throughout Boston and surrounding municipalities, is expanding to over 70 locations that were suggested by Boston’s citizens. Proposed maps can be seen on the Boston Bike Share website or the scheduled 11 open houses throughout Boston. After receiving final comments and opinions on the proposed site expansions, the stations will be created and ready for use.

Boston Hubway currently has over 1,600 bikes at over 160 stations in Boston, Brookline, Cambridge, and Somerville. The program has many affordable options, costing either $99 or $50 a year depending on income eligibility, or if one is not looking for a commitment there are 24 and 72-hour options for $8 to $15. The bikes can be picked up at any convenient location and returned at another without penalty.

As the temperatures rise, there are plenty of options for Massachusetts’s residents to safely consider alternative transportation in their future travels.

According to Professor Robert L. Ryan, FASLA, Chair of the Department of Landscape Architecture and Regional Planning at the University of Massachusetts-Amherst and UMTC Affiliate Researcher, “Boston has long been a leader in alternative transportation through its commitment to the historic Emerald Necklace of parks and trails.  Recent efforts to complete this historic vision are the exciting new Emerald Network project.”

“The Emerald Network is a vision for 200 miles of seamless shared-use greenway paths in the urban core of Boston and its adjacent cities” (Source: https://www.emeraldnetwork.info/ ) that is being proposed by the Livable Streets Alliance and is working in conjunction with the City’s efforts.

Currently, senior undergraduate landscape architecture students at the University of Massachusetts, Amherst under the direction of Professor Ethan Carr, FASLA and Assistant Professor Theodore Eisenman, PhD, MLA are working on conceptual designs for key sections of the Network as part of their senior capstone project for spring 2018.

 

Teaching Drivers to Be Safer and More Eco-Friendly

by Tracy Zafian, Research Fellow

eco
From KIA motors- This system restricts engine and transmission performance in favor of fuel economy

Real-time feedback to drivers can help them improve their fuel efficiency and safety. The results of a recent UMass Amherst field study on the Effectiveness of Eco-Driving: Real-Time Feedback and Classroom Training, were presented at the 2018 Transportation Research Board Annual Meeting, by UMass-Amherst graduate student Tao Jiang.

The presentation summarized an UMass-Amherst study undertaken as part of MassDOT Office of Transportation Planning, Research Section and funded with Federal Highway Administration (FHWA) State Planning and Research (SPR) funds. UMass-Amherst Professors, and UMass Transportation Center Research Affiliates, Dr. Daiheng Ni and Dr. Song Gao, oversaw the study. The goal of the project was “to identify and test techniques for modifying driver behavior to improve fuel economy, reduce emissions, and improve safety, in furtherance of the mission and goals of the GreenDOT Implementation Plan.”

Motor vehicles are major contributors to air pollution, and according to the U.S. Environmental Protection Agency (EPA), are responsible for close to half the volatile organic compounds that create smog, more than half the nitrogen oxide emissions, and approximately half of the toxic air pollutant emissions in the U.S.

As discussed in the research report, three major characteristics of driving behaviors to improve fuel efficiency, reduce emissions, and improve safety are:

  • Driving smoothly without much acceleration, idling, or traveling at very low speeds (such as in congested stop-and-go traffic).
  • Anticipating traffic and being vigilant about other vehicles in traffic with you and other drivers’ behaviors.
  • Following speed limits on highways and adjusting speeds as needed for adverse conditions.

The study was conducted with 133 MassDOT-owned vehicles (heavy vehicles excluded) and the employees who drive them.  The study included two types of interventions to modify driver behaviors. The first was the installation of an in-vehicle device that provided real-time feedback, including weekly emails, on each driver’s performance over a two and a half month period. The second was a 1.5-hour classroom training on eco-driving. There were four participant groups:  one that received both interventions, one that received real-time feedback only, one that had the classroom training only, and one that had no intervention. Participants’ driving behaviors were evaluated before the intervention phase, during the intervention phase, and afterward.

Major conclusions from this research were as follows:

  • Real-time feedback had a significant impact in reducing speeding and aggressive acceleration.
  • Combined effects of real-time feedback and classroom training contributed to a 0.89 mile per gallon improvement in fuel economy.

The study recommended that both real-time feedback and training, as well as periodic follow-up and monitoring, will maximize the effectiveness of such eco-driving interventions.

Getting Around on Two Wheels, with a Motor, Instead of Four

by Tracy Zafian, Research Fellow

e-bike-

MassDOT’s sustainability initiative calls for reducing greenhouse gas emissions (GHGs) and for promoting transportation modes such as bicycling, walking, and public transit. Electric bikes are a viable, environmentally-friendly way to get around.

Electric bikes, also known as e-bikes, are bicycles with an electric assist motor attached to the frame. With some e-bikes, the motor supplements pedal power as needed; with other e-bikes, the rider can choose to not pedal at all. There are currently close to 230 million e-bikes worldwide. They are especially popular in China, which has over 200 million of them, in other parts of Asia, and in European countries such as Germany and the Netherlands. U.S. e-bike sales are small compared to sales in other parts of the world, but U.S. sales are growing. It’s estimated that 263,000 e-bikes were sold in the U.S. in 2017, an increase of 25% over the previous year.

As described on an e-bikes website, e-bikes “provide all the advantages of a regular bicycle: fun exercise, free parking, zero emissions, and freedom from gridlock, while eliminating one of the bicycle’s more serious drawbacks, lack of power.” Because of their power assist, including on hills and with longer distances, e-bikes can be an option for people who might otherwise not be willing, or able, to bicycle for certain trips. This includes people traveling to work who don’t want to get sweaty during their commute and have to change or shower at the end of their trip.  It also includes older people who would stop biking without power assist.

E-bikes are also environmentally friendly. Transportation researcher Mirjan Bouwman from the Netherlands has estimated that e-bikes are thirteen times more energy efficient than a typical four-door car and six times more energy efficient than rail transit. E-bikes are also less expensive than a car. A typical e-bike sold in the U.S. costs between $1,000 and $3,000. In some situations, families have decided to purchase an electric bike, in lieu of having a second car. One example of a versatile e-bike is the cargo bike.

Some bike sharing programs now have e-bikes, which can help make them more affordable and further increase their use. The first e-bike only bike share program in the U.S. started last summer in Park City, Utah. Another e-bike bike share will be starting this year in the cities of Davis, Sacramento, and West Sacramento, California. Some regular bike share programs, such as in Birmingham, Alabama, have expanded to include e-bikes. In Massachusetts, bike share programs currently exist or will be starting up this year, in a number of cities including Boston, Worcester, Revere, and Quincy. None of the Massachusetts bike share programs includes e-bikes yet.

As e-bikes have become more popular, some cities have restricted or prohibited their use, citing safety concerns. This has been the case in a number of Chinese cities, and in New York City as well.

In Massachusetts, a bicycle is considered a “low-speed electric bicycle” under Federal law (15 U.S.C. § 2085) that does not have to be registered with the state Registry of Motor Vehicles (RMV) if it meets all of the following criteria:  has as two or three wheels; has fully operable pedals; has an electric motor of less than 750 watts (one horsepower); and has a maximum speed of less than 20 miles per hour (mph) on a paved level surface, when powered solely by the motor.  “Low-speed electric bicycles” can be used on any roadways that bicycles can, and anyone under age 16 who is riding one is required to have a helmet.

MassDOT Earns its First LEED Gold Certification

by Courtney Murtagh, UMTC Intern

LEED

In 2016, MassDOT’s Research and Materials lab was nationally recognized and awarded Leadership in Energy and Environmental Design (LEED) Gold certification. The award-winning MassDOT facility, located near the Massachusetts Turnpike, was designed by Elkus Manfredi Architects. The LEED certification is a globally recognized award commending sustainable and efficient building design.

The lab is used to run tests on concrete, soils, asphalt, chemicals, and other material for MassDOT Highway Division construction projects. The facility is responsible to evaluate materials for more than 500 ongoing construction projects at any given time.

The building achieved its high rating certification with its sustainable site development, water savings, energy efficiency, renewable materials, and high indoor environmental quality, according to a MassDOT press release.

The building is also equipped with other state-of-the-art green technology including porous pavement for runoff rainwater to charge the water table directly, two dual-port Level-II Electric Vehicle charging stations and a photovoltaic (PV) system that is expected to generate about 675,000-kilowatt hours (kWhs) per year. That energy output is roughly equivalent to 75% of the facility’s projected annual demand, according to the press release.

The Baker-Polito Administration is committed to reducing greenhouse gases (GHG) and increasing energy efficiency. Improving transportation infrastructure is one way the administration is approaching this goal.  “MassDOT’s state-of-the-art Research and Materials lab has many environmentally-friendly features including approximately 500 kW of Solar-Carports, about 40 kW of Rooftop PVs, and south-side self-tinting windows that limit over-heating in the summer and winter, and increase energy efficiency while making the workplace more comfortable for people inside,” said Transportation Secretary and CEO of MassDOT, Stephanie Pollack. The Highway Division is focusing on reducing GHG emissions by reducing the energy and chemicals used in maintenance projects, bettering the ecological performance of land under MassDOT care and control, minimizing exposure to hazardous waste, adapting facilities for climate change resilience, and minimizing developed land use altogether.

The Baker-Polito Administration hosted a series of listening sessions throughout the Commonwealth in late October and early November 2017 to discuss possible ideas and solutions for reducing GHG emissions from the transportation sector. The listening sessions were held in response to the Massachusetts Global Warming Solution Act (2008) and Governor Charlie Baker’s Executive Order 569, An Order Establishing an Integrated Climate Change Strategy for the Commonwealth. The specific regulations of the Executive Order require the Commonwealth to reduce GHG emissions by 25% below the 1990 emissions level by 2020 and by 80% below 1990 levels by 2050. As of 2014, the Commonwealth had reduced emissions to below 21% of the 1990 emissions.

 

MassDOT Research on Commuter Bus Demand, Incentives for Modal Shift and Impact on GHG Emissions

by Matt Mann, Research Program Coordinator

ghg

In January 2018, two UMass Transportation Center Research Affiliates, Assistant Professors Eleni Christofa and Eric Gonzales, presented the results of the MassDOT research project Commuter Bus Demand, Incentives for Modal Shift and Impact on GHG Emissions at an Executive Briefing at the MassDOT Office of Transportation Planning (OTP). The meeting was attended by OTP and Rail & Transit Division staff with a variety of transportation expertise. This research aimed to identify corridors in the Boston metropolitan region for which new or expanded express commuter bus service could have the largest impact on reducing greenhouse gas (GHG) emissions.

The research objectives of this project centered on:

  • Developing a data-based model to quantify the effect of new commuter bus service on user cost, agency cost, and GHG emissions, by accounting for changing mode shares.
  • Applying models to optimize potential commuter bus services and identify corridors with the greatest potential for GHG reduction.

Preliminary findings discussed at the Executive Briefing include:

  • Existing models and data centered on cost models, GHG emissions models and mode choice models.
  • Status quo mode share and GHG emissions for commuting corridors.
  • Developing a model for new commuter bus service, including user and agency costs for new services.
  • Developing a method to optimize expanded bus service
  • Prioritizing origin-destination pairs with the greatest reduction in GHG and the maximum cost efficiency.

The final report will be available in the spring of 2018.

 

 

100% Renewable Transportation by 2045 – Hawaii is Leading the Charge

by Courtney Murtagh, UMTC Intern

100%

In December 2017 Hawaii’s four Mayors committed to 100% renewable public and private transportation by 2045. Meaning all of Hawaii’s cars, busses, trucks and trains will use renewable energy as fuel.

The four mayors – Honolulu Mayor Kirk Caldwell, Maui County Mayor Alan Arakawa, Kauai County Mayor Bernard Carvalho Jr. and Hawaii County Managing Director Wil Okabe, representing Mayor Harry Kim – signed their respective proclamations, solidifying Hawaii’s status as a nation leader in renewable energy.

Hawaii has always been on the forefront of sustainability and in many ways is leading the nation. In 2015, Hawaii’s Governor David Ige signed into law a bill to reach 100% renewable energy consumption by 2045. In June 2017, another law was passed and Hawaii was once again the first state to commit to the Paris climate accord, despite President Trumps decision to pull the U.S. out of the agreement.

Despite Hawaii being the second in the U.S for electric vehicles sales per capita, Hawaii’s ground transportation still accounts for over a quarter of the states imported fossil fuel consumption as well as a quarter of greenhouse gas emissions.

Exuberant gas prices due to the Islands geography and the high cost of importing oil are the reason many Hawaii citizens are readily accepting this act. Locals and leaders alike are hoping that renewable transportation will reduce the cost of living as well as attract businesses and create jobs.

Hawaii is the first state to commit to this goal, but other states including Massachusetts may not be far behind.

In September 2017, a hearing was held to consider the 100% Renewable Energy Act, which would put Massachusetts on the path to obtain 100% of its electricity from renewable resources by 2035, as well as heating and transportation by 2050.

The Bill (S.1849) passed the House on January 23 and is currently being referred to the joint committee on telecommunication, Utilities and Energy.

More than 40 U.S. cities and 100 global companies have committed to 100% renewable energy.

Uber, Lyft…Impacting Traffic and Economic Development

by Matt Mann, Research Program Coordinator

 

uber

People are taking Uber, Lyft or Transportation Network Companies (TNCs) more these days and often to avoid both parking and drinking and driving.  Although the majority of users are urban base, demand has been increasing in suburbia for Ubering.  TNCs have changed the way people get around and have impacted traffic in many cities.  If these types of rides are a pre-cursor to autonomous vehicles, the additional passenger trips will continue to increase and will also impact economic development.

A recent U.C. Davis study that included 4,000 users in seven major metro areas—Boston, Chicago, Los Angeles, New York, the San Francisco Bay Area, Seattle, and Washington, D.C., between 2014 and 2016 – points to cities increasing in passenger trips and in population, but transit rides and taxi trips decreasing.  The TNCs are the main source that are accommodating the increase in trips and in-turn causing more urban traffic congestion.

This study also found that around 50% of these trips would not have happened at all or would have been done some other way, via transit, walking etc…This coupled with the dead head time, when no passengers are in the vehicle, the TNCs are having a dramatic impact on vehicle miles traveled and congestion.

Currently New York City is the only major metropolitan city that mandates TNCs to report their travel data.  Other cities are able to obtain data but TNCs are not required to share it.  Being able to access and analyze this data can be the key to determining current and future traffic impacts.

Massachusetts passed legislation in 2016, creating a regulatory framework for TNCs. Speaking with Katie Gronendyke, Press Secretary, Executive Office of Energy and Environmental Affairs, the MA Department of Public Utilities Transportation Network Companies Division  does require some TNC travel data to be reported:

274.12: Reporting Requirements

(2) Annually, a TNC shall report to the Division the following: (a) By February 1st of each calendar year, a TNC shall submit a report for the number of Rides from the previous calendar year, including: 1. City or town where each Ride originated; 2. City or town where each Ride ended; 3. Aggregated and anonymized trip route and length (miles and minutes); and 4. Location of Vehicle accidents;

(b) By March 31st of each calendar year, a TNC shall report its intrastate operating revenues for the previous calendar year. If a TNC fails to report its intrastate operating revenues to the Division by March 31st of any calendar year, the Division may estimate a TNC’s intrastate operating revenues. A TNC’s intrastate operating revenue shall include but not be limited to any Rider picked up at the following: 1. Airport; 2. Train station; 3. Bus terminal; or 4. Any other kind of port.

A Big GHG Reduction – An Entire Bus Fleet Goes Electric

by: Matt Mann, Research Program Coordinator

Image result for electric buses stations

Approximately 16,000 diesel buses were replaced with 16,000 electric buses, in the city of Shenchen, China.  This is the single largest replacement for electric buses to-date.  The mass overhaul included not only getting rid of over 16,000 diesel buses, it also included connecting over 500 charging stations and installing over 800 poles to charge the buses.

Not only are the environmental benefits big, with the reduction of Green House Gas (GHG) emissions; the city of Shenchen has become a quieter city, less the bus engine noise.  The city is also on track for long-term cost savings, in the order of not relying on 75% of the bus fuel coming from fossil fuels.

The recently completed MassDOT project Zero Emission Transit Bus and Refueling Technologies and Deployment Status, championed by Lily Oliver, Office of Transportation Planning. This report summarizes the characteristics of three Zero Electric Buses technologies: 1) battery electric buses; 2) fuel cell battery electric buses; and 3) fuel cell plug-in hybrid electric buses, as well as relevant implementations in the U.S., through a comprehensive review of the available literature, an online survey of several transit agencies that have implemented or are planning to implement ZEBs, and interviews with transit agency representatives. The focus is on performance and cost characteristics of these technologies as well as implementation approaches, refueling strategies, and funding mechanisms.

Transportation Sector – Moving from GHGs to Electricity

by: Matt Mann, Research Program Coordinator

Gas vs Hybrid

As Greenhouse Gases (GHGs) continue to contribute to climate change, the biggest contributor is now the transportation sector, taking over from the power plants.  This doesn’t mean there are more emissions coming out of tailpipes; rather less coal is being used and an increase in cleaner natural gas are two of the biggest reasons.  In the long-term, the other reason could also include an increase in demand of electric vehicles.

Transportation emissions have been fairly flat since 2000 and with a slight increase since 2012.  This, coupled with an increase in the way electricity emissions are produced, has allowed planes, trains and automobiles to become the lead emitter of GHGs since the late 1970s.  Electricity demand has also leveled off, as the shift has been away from coal and more on natural gas and renewable energy.

Even though electricity demand has leveled off, the increase demand for electric vehicles could change this.  With a minimal but consistent increase over the last couple of years, electric vehicles are expected to widen their reach and even include electric delivery trucks as well. With electric vehicles becoming more affordable, reliant and convenient, this increase in demand could eventually have a big impact on pollution emitted.

There are a couple recently completed MassDOT research publications on GHGs reduction and electric vehicles, written by One Center Research Affiliates Erin Baker and Song Gao.  Also Shannon Greenwell, from the Office of Transportation Planning at MassDOT, is currently working on a review and analysis of low-cost, quick to deploy, and scalable GHG-reducing investment strategies that would supplement traditional capital investments.