The seminars are supported by the Toulan School of Urban Studies and Planning and the Department of Civil and Environmental Engineering, and the National Institute for Transportation and Communities (NITC).
Unobserved Heterogeneity and Spatial Correlation: Statistical and Econometric Analyses of Heavy-Vehicle Hard Braking and Crash Frequency
In heavy-vehicles (a truck with a gross vehicle weight rating of greater than 10,000 pounds), a hard braking event is described as an event that prompts the vehicle’s “black box” to record an abrupt change in speed. More specifically, this occurs when the driver applies excess force to the vehicle’s brake. These hard braking events can then serve as a proxy for several factors, such as economic impacts, environmental impacts, and impacts on safety. In the context of the present study, being that approximately one-third of all heavy-vehicle-caused crashes in 2014 were attributed to faulty brakes, there is a need to better understand heavy-vehicle hard braking and its impact on safety for all highway users. Therefore, the current study utilizes a previously unused freight data source to identify statistically significant heavy-vehicle hard braking hot spots.
Upon merging several datasets, crash data is spatially joined to the hard braking hot spots to conduct a crash frequency analysis of the four crash types that occurred most often: rear-end crashes, turning movement crashes, fixed-object crashes, and sideswipe (overtaking) crashes. Applying advanced statistical and econometric methods, a set of random parameters models and a set of spatial lag models were fit to determine if accounting for unobserved heterogeneity or spatial correlation provides better parameter estimates, overall model fit, and higher prediction rate of crash frequencies for crashes at heavy-vehicle hard braking hot spots. Results show that several exposure-based variables impact the expected number of crashes, such as traffic volume, roadway characteristics, posted limits, etc. In terms of the preferred modeling framework, the spatial lag models provided a slightly better overall fit and correctly predicted more crash counts for the given datasets. This suggests that transportation agencies and safety practitioners should explore the impact of spatial correlation (as well as unobserved heterogeneity) when conducting safety analyses and generating specific safety performance functions.
In 2016 the United States Department of Transportation (USDOT) Federal Highway Administration (FHWA) published a Guidebook for Developing Pedestrian and Bicycle Performance Measures that presents methods for measuring walking and bicycling performance and activities and embedding them into the transportation planning and decisionmaking process (U.S. Department of Transportation 2016). Building on the 2016 guidebook, this resource focuses on pedestrian and bicycle network connectivity and provides information on incorporating connectivity measures into state, metropolitan, and local transportation planning processes.
Connectivity measures can help transportation practitioners identify high priority network gaps, implement cost-effective solutions that address multiple needs, optimize potential co-benefits, and measure the long-term impacts of strategic pedestrian and bicycle investments on goals such as improving safety, system efficiency, network performance, and access to key destinations. Toward that end, this resource should be used in conjunction with self-evaluation and transition plans to evaluate needs for pedestrians with disabilities.
What Is Multimodal Network Connectivity? Connectivity is one of several concepts commonly used in transportation performance measurement to describe the ease with which people can travel across the transportation system. At its simplest level, network connectivity addresses the question, "Can I get where I want to go easily and safely?" Multimodal network connectivity adds the dimension of travel choices to the picture: "Can I get where I want to go easily and safely in whatever way I choose-for example, walking, bicycling, using transit, or driving?" A connected multimodal network allows people to travel by whatever mode they choose, including people who do not drive or do not have access to a motor vehicle.
Key Components of Pedestrian and Bicycle Network Connectivity This guidebook outlines five core components of multimodal network connectivity, as listed below, with a focus on pedestrians and bicyclists. While these components are all related, the distinctions between them provide a framework for selecting connectivity measures that address specific questions. The guidebook describes analysis methods and supporting measures associated with each of these components:
- Network completeness - How much of the transportation network is available to bicyclists and pedestrians?
- Network density - How dense are the available links and nodes of the bicycle and pedestrian network?
- Route directness - How far out of their way do users have to travel to find a facility they can or want to use?
- Access to destinations - What destinations can be reached using the transportation network?
- Network quality - How does the network support users of varying levels of experience, ages, abilities, and comfort with bicycling or walking?
Part of the Student Presentations from TRB
Pedestrians and bicyclists are the most vulnerable road users and suffer the most severe consequences when crashes take place. An extensive literature is available for crash severity in terms of driver safety, but fewer studies have explored non-motorized users’ crash severity. Furthermore, most research efforts have examined pedestrian and bicyclist crash severity in urban areas. This study focuses on state roads (mostly outside major urban areas) and aims to identify contributing risk factors of fatal and severe crashes involving pedestrians and bicyclists in state roads. The results seem to suggest that besides improvements in roadway characteristics, additional countermeasures to reduce crash severity for vulnerable users should include educational campaigns, more strict control of alcohol intoxicated drivers, and protection strategies of senior pedestrians.
Private companies and public officials are seeking sustainable and cost effective ways to green supply chains and freight deliveries. There is enthusiasm regarding the potential benefits that innovative technologies such as drones or unmanned aerial vehicles (UAVs) can generate. This presentation discusses key issues and insights that arise from modeling the logistical, and environmental performance of UAVs.
In less than a decade, the ride-hailing industry, led by Uber and Lyft, has dramatically transformed the way we travel in our metro regions. Rider adoption of these on-demand mobility services has proceeded much quicker than our understanding of their impacts to our urban transportation systems. Planning for this transformation in personal mobility, which will have unintended consequences, has been made more difficult by the scarcity in meaningful data made available by these ride-hailing companies. Public agencies responsible for managing congestion and transit services are hindered in their ability to successfully plan for the integration of this emergent travel mode without access to these valuable data.
In response, Boston’s Metropolitan Area Planning Council conducted an intercept survey of nearly 1,000 passengers to understand who uses ride-hailing services, what types of trips are performed using these new mobility options, and how these services impact more established travel modes. Perhaps expectedly, most ride-hailing passengers were under the age of 35, use ride-hailing on a weekly basis, and do not own a car. Remarkably, however, 59-percent of surveyed ride-hailing trips added new vehicles to the region’s already congested roadways, with 42-percent of respondents stating they would have used public transit if ride-hailing was unavailable. These and other important findings provide a window of insight into the extent of ride-hailing utilization in the Boston Region and help to foster a greater dialogue about the need for data provision mandates to guide effective policy decisions.
Travis Bradley Glick
Congestion and travel delay on urban roadways can influence operating costs and service attractiveness. This research uses high resolution bus data to examine sources of delay on urban arterials. A set of tools was created to help visualize trends in bus behavior and movement; this allowed larger traffic trends to be visualized along urban corridors and urban streets. By using buses as probes and examining aggregated bus behavior, contoured speed plots can be used to understand the behavior of roadways outside the zone of influence of bus stops. Speed plots can be utilized to discover trends and travel patterns with only a few days’ worth of data. Congestion and speed variation can be viewed by time of day and plots can help indicate delays caused by intersections, crosswalks, or bus stops. This type of information is important to transit authorities looking to improve bus running times and reliability. Congested areas can be detected and ranked. Speed plots can be utilized to reevaluate bus stop locations, e.g. near-side vs. far-side, and to identify locations where improvement are needed, e.g. queue jump lanes. Transportation agencies can also benefit from this type of information because arterial performance measures are difficult to estimate.
Aaron Golub and Vivian Satterfield
There is an active debate about the potential costs and benefits of emerging “smart mobility” systems, especially in how they will serve communities already facing transportation challenges. This presentation will describe the results of an assessment of these equity impacts in the context of lower-income areas of Portland, Oregon, based on a mixture of quantitative and qualitative research.
Portland, Oregon’s proposal for the U.S. Department of Transportation’s Smart City Challenge, “Ubiquitous Mobility for Portland,” focuses on developing mobility solutions that would serve traditionally underserved populations (low-income, communities of color, and residents with mobility challenges). This study found that by lowering costs and improving service for public transit, ridesharing and active transportation, smart mobility systems could address many of the needs of transportation disadvantaged communities. Significant barriers exist, however, which prevent smart mobility technologies from benefiting all communities. For example, lower income survey respondents and respondents of color had significantly lower access to drivers’ licenses, bank accounts and credit cards, and also rely more heavily on paying cash for transit tickets. Lower income respondents and respondents of color had lower access to Internet at home and work and were more likely to reduce data use or cancel cell plans because of cost or data restrictions. Respondents were also concerned about information security, as the impacts of loss or theft, especially identify theft, can be devastating for lower-income residents.
Since integrating payment systems and relying on Internet and cell data for mobile applications is a core feature of smart mobility systems, these disparities are significant barriers to the equitable transition to smart mobility. Policy recommendations to address equity include expanding free and public WiFi, better real-time transit information, improved training, and language translation for phone applications, among other things.
Transportation Impacts of Affordable Housing: Informing Development Review with Travel Behavior Analysis
Planning for affordable housing is challenged by development policies that often do not differentiate between the travel patterns of residents of market-rate housing and those living in affordable units. The development review process generally requires an evaluation of the anticipated additional transportation demand that new development places on the system and an assessment of fees or improvements to mitigate these impacts.
However, industry standard guidelines for assessment of travel demand outlined within the Institute of Transportation Engineers (ITE) Trip Generation Handbook have been focused solely on vehicle trip rates for these traffic impact analyses. Given the public goals of providing affordable housing in areas with good accessibility and transportation options, there is a need to reduce unnecessary costs imposed by the potential over-estimation of automobile travel and its associated impacts. During the course of this seminar, we will discuss the importance of examining the influences of urban characteristics, residential housing type, and income on metrics commonly used to assess the transportation impacts of new development.
Too often, there is a gap between research and action. For researchers, peer-reviewed scientific evidence is the benchmark of success, while for policy makers and practitioners, success is being able to apply findings in the ‘real world’.
Dr Marilyn Johnson is both a senior researcher at Monash University and a practitioner at the Amy Gillett Foundation, Australia’s not-for-profit cycling safety organisation. The seminar will be a speed-dating style presentation of the latest research studies on cycling in Australia, current cycling safety campaigns and programs and the intersection between research, policy and effective action.
Content will include:
- Cyclist safety on-boarding at Deliveroo, review, recommendations and actions;
- Engaging with experts on e-bikes;
- Changing the road rules to improve safe cycling;
- Cycling skills for girls and women;
- Vulnerable road user safety training (read: putting truck drivers on bicycles), and;
- A major research study analysing coronial death investigations of fatal road crashes in Australia using public health and road safety theoretical frameworks.
Development of origin-destination demand matrices is crucial for transit planning. The development process is facilitated by transit automated data, making it possible to mine boarding and alighting patterns on an individual basis. This research proposes a novel stochastic trip chaining method which uses Automatic Fare Collection (AFC) and General Transit Feed Specifications (GTFS) data to infer an origin-destination (O-D) matrix.
Although Germany may be known internationally for its environmentalism, over the past 20 years German cities have chronically underinvested in transportation networks, both for public transport as well as non-motorized options. The lag in the development and expansion of sustainable options combined with the rapid growth in private automobile ownership (itself the result of automobile-industry-friendly policymaking) means that cities like Bremen have been left behind in terms of transportation planning. As in America, SUV sales continue to increase despite considerably narrower streets, particularly in cities.
Nowhere is this more visible than in Bremen’s Neustadt, a dense neighbourhood with the most children under ten years old, per capita, of any neighborhood in the state. Motorized traffic, much of it commuter traffic and deliveries, continues to increase with a resulting increase in noise and air pollution. Bremen’s elected officials and transport authorities are actively resisting parking controls, pedestrian crossings, traffic calming measures, measures to ensure safe routes to school, and lower speed limits; seemingly because of fear of losing votes.
Increasingly concerned neighbors are working on speed limits for a residential street. So far two official applications for a speed limit reduction from 50 Km/h (32 miles per hour) to 30 (approximately 19 mph) have been denied. A petition gathering signatures has also been denied, supposedly because there is no evidence to prove the benefits of reduced speeds, although the federal government’s own studies have shown this over and over. Our current project is for parking management and control, for example stopping cars parked illegally on sidewalks; public reception has been mixed but an open discussion is happening.
The question remains as to how citizens can actually influence and steer transportation politics in order to create real, sustainable change.
What is livability? How does the built environment influence resident perceptions of livability? Although livability is a broadly used term and a key goal in land use and transportation plans at the state level, it is unclear whether residents think their neighborhoods are livable and what contributes to their perception of livability. The purpose of the project was to understand how Oregonians, in neighborhoods of varying densities and within Metropolitan Planning Organizations (MPOs), perceive livability at the nexus of transportation and land use. We sought to understand how residents define and perceive livability in three different MPOs in the state: Albany, Central Lane, and Rogue Valley. Our survey instrument included questions about livability, satisfaction, housing choice, and preferred and current characteristics of the neighborhood and accessibility.
We found that perceptions were more influential in describing livability than objective or sociodemographic measures. We found that people tradeoff affordability and livability. When people said that housing affordability was more important in decisions about housing and neighborhood choice, they had more negative perceptions of livability in their neighborhood. But people who prioritize accessibility have a more positive perception of livability. Individuals that reported better access to transportation options across a broad range of measures reported higher ratings of livability. Pedestrian improvements and natural amenities were important to survey respondents. Finally, objective and subjective measures of density negatively impacted perceptions of livability.
The seminar will discuss the findings of this work and takeaways for planners at the local, regional, and state level.
Jenny H. Liu
As urban areas across the country are investing in bicycle and pedestrian infrastructure to promote environmentally sustainable transportation and to develop livable communities, many have pointed to improvements in environmental quality, economic development and public health as potential positive outcomes. While these outcomes of active transportation infrastructure are relatively well documented, it is also known that both transportation and environmental amenities are typically unevenly distributed in the urban context. Studies show that those who are the most socioeconomically disadvantaged (i.e. low income, people of color, etc.) are also those who disproportionately experience transportation disadvantages.
This study contributes to the existing literature by specifically linking bicycle accessibility to spatial equity analysis, using both an existing 2016 Baseline Scenario and a 2035 City Greenways Scenario in Portland, Oregon to illustrate. Two distinct types of bicycle accessibility measures are calculated: a distance-based measure (based on proximity to bicycle facilities) and a gravity-based opportunities measure (based on accessible opportunities and destinations). Improvements in bicycle accessibility are then spatially analyzed within communities identified as historically marginalized, across quintiles of identified neighborhoods and between identified communities and other areas.
Our findings suggest that although bicycle infrastructure investments generally provide greater proximity for all residents, accessibility improvements are not quite as apparent when considering access to opportunities and destinations using the second bicycle accessibility measure. The results of the various spatial equity analyses underscore the importance of integrating land use factors into transportation accessibility measures, particularly in the context of equitable access to opportunities for everyone.
Christopher Monsere and David Hurwitz
This research explored driver comprehension and behaviors with respect to right-turn signal displays with a focus on the Flashing Yellow Arrow (FYA) in a driving simulator and a comprehension survey. Flashing yellow arrows are used in place of other turn signals, such as solid green or flashing yellow or red circles, to indicate that drivers may turn after yielding to oncoming traffic. These turns are considered “permissive.” Turns where no conflicting traffic is present, such as those indicated with a green arrow, are “protected” turns. The flashing yellow arrow’s inclusion in the 2009 Manual on Uniform Traffic Control Devices sped up the signal’s adoption to indicate a permissive turn.
Results from a counter-balanced, factorial design were chosen to explore three independent variables separately: signal indication type and active display, length of the right-turn bay, and presence of pedestrians. Driver decision making and visual attention were collected and analyzed.
Walkability and walking are being intensively researched today and the literature provides a wealth of references and examples on how to measure walkability of the built environment. IAAPE is one method that was developed at the Instituto Superior Técnico (Lisbon) to measure walkability at the micro-scale, bringing solutions that were disregarded in two aspects: it is a participatory process; and it provides different evaluations for different population segments (adults, children, seniors, impaired) or for different trip motivations.
Presentation on Urban Transportation Planning and Transit-oriented development (TOD) Research in Japan.
Density Differences: Exploring Built Environment Relationships with Walking Between and Within Metropolitan Areas
Part of the Student Presentations from TRB
To explore the relationships between measures of density and walking within and between urban areas, we present an analysis of the travel survey data from six different cities from the US and Santiago, Chile. The analysis of aggregate and disaggregate pedestrian trips presented here examine the potential consistency of relationships between walking and density within and across different regions, with a specific focus on population density. Our findings illustrate a relationship between population density and walk mode shares that is roughly linear and of nearly equal magnitude across US regions in densities below 20 persons/acre. As work in this area matures, fine-grained built environment measures should be complemented with constructs that describe the metropolitan structure, including density distributions and gradients, poly-centricity, and spatial extent of the urban area.
Amy T. Parker and Prateek Dujari
Knowing where one wants to go and how to get there are essential life skills for all people. Community access and travel skills are not only important rites of passage for youth in becoming adults, they are linked to higher rates of employment and overall health. People who are blind and visually impaired (BVI) face challenges in accessing public transportation, yet studies have shown that with relevant orientation and mobility instruction, technology, and accessible design, vision loss need not preclude community travel.
Join PSU's Amy Parker and Intel's Prateek Dujari on the ways that knowledge from consumers and the field of Orientation and Mobility can positively influence design through participatory conversations. After this presentation, participants will be able to: describe the role of Orientation and Mobility (O&M) Specialists; identify features in the built environment that benefit individuals with visual impairments as well as the broader population; and identify unique needs for travelers with visual impairments in the Pacific Northwest region.
This presentation will review research regarding the economic impact of bicycle infrastructure on local businesses. Three case study corridors in San Francisco, CA are examined, and a robust discussion of the shortcomings of the research will be included. A question and open discussion period will follow, with a focus on constructive criticism of past research and methods to improve future work.
Utrecht is a bustling, bicycle-friendly city in the Netherlands. Every day, between 7 a.m. and 7 p.m., over 125,000 cyclists ride to their work, school, university, public transport, shops or home through the city centre.
The municipality wants to make cycling even more attractive for these and other cyclists. Consequently, the bicycle is given precedence in the mobility policy of the municipality of Utrecht. We want to be the most bike-friendly city in the world. We want to keep our growing city livable, accessible and economically strong, and we are convinced that the bicycle can and should play a major role in this.
This presentation will give insight in the biking policy, bicycle parking and enforcement, bicycle infrastructure and routes, construction and detours, economics, and safety in Utrecht.
How can we encourage people to make use of the transportation systems in place - to improve transit ridership and, in turn, to improve the health and happiness of our societies?
New findings in behavioral science could unlock new, more effective ways to change transportation behavior...but only if we have a way to find and use that evidence. TransLink (Vancouver BC) undertook a groundbreaking research effort to use cognitive biases to explain why people drive today, and and to identify possible "nudge" strategies to shift those trips to transit and active modes. The resulting report includes brand-new ideas that area ready to be tested by practitioners. Join us to learn about how academics and practitioners can join forces to create mode shift programs that work.
Part of the Student Presentations from TRB
Researchers have been parsing which components of the built environment contribute to outcomes of interest and to what degree, particularly the effects on vehicle use and walking. Increasingly, researchers and practitioners recognize that the type of neighborhood may affect individual travel behaviors. These bundle of various land use and transportation system characteristics can be constructed as different neighborhood or place types. But not all place types are constructed with the same use, purpose, or methods. This presentation will review three classifications of place typologies to better understand their purpose and appropriate application as well as introduce an online transportation platform that will incorporate aspects of place type.
Investments into active transportation infrastructure are often promoted as a strategy for sustainable transportation, better public health, environmental quality, and economic development. Although empirical evidence generally points toward positive property value impacts of off-street greenways and trails, few focus on whether households might have different willingness-to-pay for different types and levels of bicycle infrastructure. This paper aims to fill research gaps in understanding consumer preferences for different types of bicycle facilities by examining property value impacts of four bicycle facility types: on-street advanced bike facilities and bike lanes; and off-street regional multi-use paths and local multi-use paths. Using Portland, Oregon as a case study, this paper applies spatial hedonic pricing models, and characterizes each facility type by both ease of access (distance) and extensiveness of bike network (density) within a range of buffer zones.
We find strong evidence that households prefer to be located close to advanced bike facilities and enjoy a denser network. However, these impacts are not consistent across all types of bicycle facilities. Bike lanes tend to contribute negatively to property values. Model estimations also indicate some positive consumer preference for proximity to local multi-use paths, generally located within urban greenspaces. In addition, extensiveness of on-street bicycle facilities show positive and statistically significant impacts on property values, with diminishing effects as the buffer zone radius is increased. The results of this study should provide practical evidence for planners and policy makers in understanding the range of consumer preferences for various types of bicycle infrastructure investments.
How can we go one step, or one lane, further than the standard road diet? Roundabouts allow a road diet to reduce the final number of lanes from three to two.
Questions arise when roundabouts are used with a road diet. What traffic volumes are supportable? Will the roundabouts fit within existing intersections? What does current guidance tell us about this approach?
Michael Williams will present his work on creating a sequel to FHWA’s Road Diet Informational Guide. This work is intended to provide a feasibility determination tool for the application of this approach to existing corridors. Data from Bird Rock Boulevard in La Jolla, CA is presented as an example from which important lessons are drawn.
Part of the Student Presentations from TRB
Integrated land use and transportation models have evolved along a spectrum with simplistic sketch planning models on one end and sophisticated microsimulation models on the other. While each type of these models has its niche, they are largely unable to balance the flexibility and realism of microsimulation and the speed and interactiveness of simple models. The Regional Strategic Planning Model (RSPM) aims to fill this gap by taking a microsimulation approach but making other simplifications, to model first-order long-term outcomes of land use and transportation quickly. It takes into consideration the underlying uncertainties of long-term modeling by accepting a broad range of policy inputs and technology assumptions while allowing rapid simulations of hundreds of scenarios. The RSPM is one of a few operational modeling packages (along with EERPAT and RPAT) that have evolved from GreenSTEP, a microsimulation modeling package for state-level evaluation of strategies for reducing transportation energy consumption and greenhouse gas (GHG) emissions. Several ongoing projects are aiming to develop a common software framework for the family of strategic modeling tools and improve the policy sensitivity of multi-modal travel. In this study, we introduce the RSPM framework, and then primarily focus on the new development of a multi-modal travel demand module that links various policy inputs to households’ multi-modal travel and further to aggregate transportation outcomes (e.g. GHG emissions, traffic fatalities). We discuss our choice of model structures and specifications and then estimate the models utilizing a unique US nationwide dataset combining the 2009 US National Household Travel Survey (NHTS), EPA’s Smart Location Database, and the National Transit Database. This comprehensive dataset provides a rich set of variables capturing household social-demographics, multi-modal travel, built environment, and transportation supply. We conclude the paper with the results of validation and sensitivity tests, and a discussion of future work.