Renewable Energy in the Right of Way


At SSTI’s first Sustainability Directors Community of Practice meeting in June 2015, attendees discussed their states’ interest in siting solar and other renewable energy generation facilities in the highway right-of-way but cited uncertainty regarding FHWA rules and unfamiliarity with the business side of renewable energy production as major hurdles. In an effort to support these efforts and allow interested states to learn from others, SSTI has gathered the technical documents gathered here, under the headings below, comprise a living repository for state DOTs and others to use as examples as they develop their own ROW renewable energy projects. Read More >

Trip-making and accessibility: New tools, better decisions (SSTI, 2016)

Madison access pic

Transportation researchers and practitioners have long sought other tools to complement or perhaps replace conventional methods—tools that would better analyze trips rather than speed at points in the system, speak to non-auto modes of travel, address land use solutions as well as highway infrastructure, and so on. Fortunately, new sources of data and emerging methods, as well as new-found interest in performance and scenario planning, are yielding the types of tools that the field needs. Read More >

Effects of Parking Provision on Automobile Use in Cities: Inferring Causality (McCahill, Garrick, Atkinson-Palombo and Polinski, 2015)


Automobile use has been on the rise in cities for nearly a century and so has the supply of parking. Because driving often seems unavoidable, policymakers, developers and the public push endlessly for more parking to meet demand. That push, however, might only be making matters worse. SSTI Senior Associate Chris McCahill’s research suggests that abundant parking in cities causes people to drive more, shedding important light on the question of cause and effect. Read More >


Trip-making data, TDM, and connectivity in Northern Virginia (SSTI and Michael Baker International, 2016)

Commercially available GPS data offers valuable new insight about trip origins, destinations, and routes, including short trips that travel demand models often cannot capture. Using this data, SSTI worked with Michael Baker International, the Virginia DOT, and local stakeholders to identify opportunities for managing travel demand and improving connectivity throughout Northern Virginia. This final report describes the full data set and 17 selected case studies, along with recommended projects and policies, estimated costs, and benefits for each. More Resources...


A preview of the driverless-vehicle future: Uber and other TNCs are cannibalizing New York’s transit ridership and worsening congestion and emissions

The effect of transportation network companies is one of the central concerns of transportation planning, in part because TNCs can provide a hint about what might happen when driverless vehicles become widely available. In addition, to date the lack of TNCs’ willingness to share data has limited our ability to assess these effects. A new report focusing on these services in New York City, sheds welcome new light on the topic, and provides plenty of evidence for pessimism about the sustainability of TNCs, conventional or driverless, without significant policy intervention. Read More >

Unpacking the rise in traffic deaths

Traffic deaths shot up for the second straight year in 2016, according to recent estimates from the National Safety Council. To make better sense of what drove the increase in deaths, we compiled FARS data through 2015—the first year of the recent spike—and separated crashes by type. What does this all tell us? To begin with, there’s no silver bullet for improving road safety, short of reducing the amount we drive. Regulations, enforcement, and education aimed at young drivers and distracted driving could have a substantial impact if they are effective. But additional responsibility falls on road designers. Read More >

Dividing the pie: Maryland lawmakers take on transportation project selection

The Maryland legislature on April 8, 2016 overrode a gubernatorial veto in order to pass a transportation project scoring bill that will rank and ultimately help select major capital projects. The legislation and new ranking system is similar to Virginia’s Smart Scale, which ranks and prioritizes transportation projects throughout the state. Unlike Smart Scale, which was a bipartisan effort with gubernatorial support, Maryland’s effort has hit a major road block, challenged by a lack of critical gubernatorial support. Read More >

Downtown Seattle’s drive-alone commute share drops to 30 percent

Despite an influx of jobs in Seattle’s downtown area, the number of people driving to work has barely changed since 2010. According to a survey from Commute Seattle, a non-profit working with downtown employers, the working population in and around downtown increased by 45,000 in the past six years, but drive-alone commutes increased by approximately 2,255 morning trips. Drive-alone commute mode share decreased from 35 percent to 30 percent in the same time period. So how did the city accomplish that? Read More >

SSTI research highlights built environment policies to reduce VMT

As part of a larger 2015 project for the Commonwealth of Massachusetts, SSTI investigated the influence of six built environment variables on passenger vehicle miles traveled. Using data on average daily household VMT at the Census block group level from the Massachusetts Registry of Motor Vehicles, along with detailed land use data and transportation system information, we were able to determine how VMT varied according to a number of variables. Read More >

More News...