An increasing trend in the number of bicycle crashes in the U.S since 2009 has been a major challenge to safety. A new PSU masters thesis in civil engineering offers insights: "Improving Bicycle Crossings at Unsignalized Intersections through Pavement Markings: Analysis of the City of Portland Innovative Strategy" by Frank Boateng Appiah of Portland State University.

For a deeper dive into this research, read BikePortland's coverage of the study. For more on the researcher, read our 2020 interview with Frank.

The City of Portland, Oregon has experimented with an innovative treatment to improve bicycle crossings at unsignalized intersections. This treatment, termed a high visibility cross-bike, was installed at crossings of neighborhood bicycle greenways with busy roadways. The marking is similar to a zebra-striped pedestrian crosswalk but with green pavement markings rather than white. Although the cross-bike marking does not currently require motorists to yield for bicycles waiting to cross the roadway, it was hypothesized that the presence of the marking would alter motorists' yielding behavior towards bicyclists and improve the crossing experience for persons on bicycles.

In his thesis, Appiah analyzed empirical data to evaluate the modifications in the rate of motorists' yielding behavior at three unsignalized intersections in Portland, Oregon. The intersections (NE Going and NE 15th Ave, SE Salmon and SE 20th Ave, NE Holman and NE 33rd) were evaluated before and after the new markings were installed. 

Video data revealed changes in the rate of motorists yielding to bicyclists. Notably, the analysis found that the installation of the cross-bike improved driver yielding behavior for cyclists. This change in driver yielding was statistically significant. Driver yielding rates at NE Going & NE 15th Ave were found to be 48% near side and 61% far side before the crossing was marked. These yielding rates improved to 91% near side and 95% far side after the installation of the treatment. This statistically significant difference in yielding behavior of motorists is expected to translate into improved bicycle safety.

In addition to increasing motorists' yielding rates, the cross-bike markings also reduced average wait times for persons on bicycles, and provided positive guidance for bicyclists to select a more visible crossing location. It can be expected that the number of people using the bicycle network will increase if the safety and efficiency of the crossings are improved. Excessive delays at busy crossings put off many interested but concerned cyclists.

Photo by Cait McCusker

The Transportation Research and Education Center (TREC) at Portland State University is home to the National Institute for Transportation and Communities (NITC), the Initiative for Bicycle and Pedestrian Innovation (IBPI), and other transportation programs. TREC produces research and tools for transportation decision makers, develops K-12 curriculum to expand the diversity and capacity of the workforce, and engages students and professionals through education.

Tags

Researchers Amy Parker, Martin Swobodzinski, Julie Wright, Kyrsten Hansen and Becky Morton of Portland State University, along with Elizabeth Schaller of American Printing House for the Blind, have published a literature review in Frontiers in Education: Wayfinding Tools for People With Visual Impairments in Real-World Settings: A Literature Review of Recent Studies.

The literature review, published in October 2021, and a case study published in September 2021 in the same journal are both related to an ongoing project led by Swobodzinski. The project, Seamless Wayfinding by Individuals with Functional Disability in Indoor and Outdoor Spaces: An Investigation into Lived Experiences, Data Needs, and Technology Requirements, is funded by the National Institute for Transportation and Communities (NITC).

The October article reviews 35 peer reviewed articles in order to identify and describe the types of wayfinding devices that people who are blind, visually impaired or deafblind use while navigating indoors and/or outdoors in dynamic travel contexts.

Within this investigation, the researchers discovered some characteristics of participants with visual impairments, routes traveled, and real-world environments that have been included in recent wayfinding research as well as information regarding the institutions, agencies, and funding sources that enable these investigations.

Results showed that 33 out of the 35 studies which met inclusionary criteria integrated the use of smart device technology. Many of these devices were supplemented by bluetooth low-energy beacons, and other sensors with more recent studies integrating LIDAR scanning. Identified studies included scant information about participant’s visual acuities or etiologies with a few exceptions, which limits the usability of the findings for this highly heterogeneous population. Themes derived from this study are categorized around the individual traveler’s needs; the wayfinding technologies identified and their perceived efficacy; the contexts and routes for wayfinding tasks; and the institutional support offered for sustaining wayfinding research.

Human wayfinding and navigation allow human beings to fully participate in the environment and are essential elements for leading healthy, economically sustainable, and full lives. The NITC project aims to drive forward the development of standards and innovation in mobile wayfinding as it relates to the integration of indoor and outdoor wayfinding and routing of visually-impaired, blind, and deafblind pedestrian travelers.

Photo by Halfpoint/iStock

The National Institute for Transportation and Communities (NITC) is one of seven U.S. Department of Transportation national university transportation centers. NITC is a program of the Transportation Research and Education Center (TREC) at Portland State University. This PSU-led research partnership also includes the Oregon Institute of Technology, University of Arizona, University of Oregon, University of Texas at Arlington and University of Utah. We pursue our theme — improving mobility of people and goods to build strong communities — through research, education and technology transfer.

Tags

Low-income residents, immigrants, seniors, and people with disabilities – these are people who stand to gain the most from new tools and services that reduce transportation costs and travel time. However, issues of affordability, technology adoption, banking access or other barriers can limit access to these new mobility opportunities.

In the latest report funded by the National Institute for Transportation and Communities (NITC), New Mobility For All: Evaluation of a Transportation Incentive Program for Residents of Affordable Housing in Portland, OR, Portland State University researchers Nathan McNeil, John MacArthur and Huijun Tan worked with the City of Portland’s Bureau of Transportation (PBOT) to evaluate a local pilot program: the Transportation Wallet for Residents of Affordable Housing. This program provides a set of transportation incentives for low-income participants, including:

  • a $308 pre-paid US Bank Visa card which could be applied to public transit or other transportation services,
  • a free BIKETOWN bike share membership, and
  • access to discounted rates on several services.

Researchers surveyed the program’s participants to understand how they used the Transportation Wallet and how it helped them use different modes to get around Portland, OR. The goal was to identify which aspects of "new mobility" services (e.g. Uber/Lyft, bike share and e-scooters) appeal to different underserved groups. Drawing on the survey results, the researchers developed potential strategies to expand the reach and value of these transportation services, and consider how to implement more programs to realize these benefits. 

"The research highlights a specific group of individuals and families who are historically underserved, who often have limited access to services and jobs, and lack mobility options. The Transportation Wallet program is an innovative approach to address their mobility needs. This research focuses on evaluating the pilot program, but there is still so much to learn and understand how cities, transit agencies and mobility providers can assist the people living in affordable housing communities," MacArthur said.

The research team shared insights from the findings in a February 2021 paper in Transportation Research Record: "Evaluation of a Transportation Incentive Program for Affordable Housing Residents."

HOW DID PEOPLE USE THE WALLET?

"The Transportation Wallet provided funds for participants to use on transportation services, but it didn't prescribe specifically how they should use it. We ended up seeing a real variety. Some used it exclusively for public transit for daily needs, others for the occasional Uber or Lyft trip, and some people explored new services like our shared e-bike system or e-scooters. We also heard from a lot of participants that the program made them feel more independent in terms of being able to get around the city, as well as having less stress about if they or their children would be able to get home in the event of a missed bus or ride," McNeil said.

The research team found some key findings on how the Transportation Wallet was used:

  • A majority of the low-income participants were already users of TriMet –Portland’s public transit agency. Nearly half of the respondents indicated that they tried to use new modes that they never used before with the Transportation Wallet, which was correlated with increased sign-ups and usage of ride-hail, e-scooter and bike share services.
  • Participants appeared to use each mode more than they would have otherwise.
  • The flexibility and convenience of the program were highlighted in survey comments by participants. Responses also indicate that the program reduced stress related to how people might meet their basic travel needs or get around in the case of unexpected or emergency travel needs, all while reducing financial stress as well.
  • Although TriMet and ride-hail were the most used among the available services, it is still notable that 28% to 29% of participants signed up for e-scooter and bike share services, even if many did not proceed to use them. This highlights the potential of such a program, but also speaks to the need for programs to engage further in helping transition people from signing up for a service to actually using that service.

IMPLEMENTING A SIMILAR PROGRAM

RECRUITING PARTICIPANTS AT TRANSPORTATION FAIRS

"For anyone providing this type of service, keep in mind the value of Transportation Fairs. Attendees at these in-person events were much more likely to sign up for services, including discounted TriMet fares. Hosting the fairs near people’s homes was seen as very important by both the people we surveyed and the partner housing agencies," McNeil said.

To the extent possible, researchers recommend that participants should leave the Transportation Fairs "ready to walk out the door and start using the Transportation Wallet." Having activated cards to distribute at the fair (or providing credit to participants through a mobile app) could help to encourage program participation generally, and help in further promoting some of the services that participants may not have previously tried.

OPPORTUNITIES TO IMPROVE

Input from participants suggests that several aspects of the Transportation Wallet can be improved:

  • Improve the way information about the program and new mobility usage is conveyed, specifically for those who never use phone apps to travel around.
  • Explore participants’ experiences when using different services. For instance, safety concerns about bike share and e-scooter share services and age-related barriers (e.g., physical ability) was a challenge. This is consistent with previous studies about safety concerns as a barrier for using new mobility. Transportation agencies may be limited in their promotion of these modes without further strategies to address the different perceptual and objective barriers.
  • Address problems through an enhanced level of ongoing assistance. This could include help with activating their Transportation Wallet cards, transferring funds into their service accounts, and navigating the challenge of prepaid cards which were sometimes not an acceptable form of payment. This type of further assistance could also help to address the gap between the number of people who sign up for various services and those who actually use those services.
  • Increased opportunities to actually test out services (use the apps, ride the e-scooters and bike share bikes). Some participants could benefit from lessons and practice in using e-scooters, bikes, ride-hail, and transit. Having tried it once in a supportive environment could be all it takes to give someone the confidence to use a new mode going forward.

Cities interested in implementing similar transportation programs can use the insights from this report on the Portland pilot study. Overall, the message from the Transportation Wallet program is one of empowerment: it did make it easier for many transportation-disadvantaged participants to get around, and gave them a new freedom of choice between different modes they hadn't explored before. For those who want to replicate this experiment, this report offers detailed guidance and a positive model to build upon.

ABOUT THE PROJECT

New Mobility For All: Can Targeted Information And Incentives Help Underserved Communities Realize The Potential Of Emerging Mobility Options?

Nathan McNeil and John MacArthur, Portland State University

This research was funded by the National Institute for Transportation and Communities, with additional support from Metro, the Portland Bureau of Transportation, and Portland State University.

RELATED RESEARCH

To learn more about this and other NITC research, sign up for our monthly research newsletter.

Photo by Cait McCusker

The National Institute for Transportation and Communities (NITC) is one of seven U.S. Department of Transportation national university transportation centers. NITC is a program of the Transportation Research and Education Center (TREC) at Portland State University. This PSU-led research partnership also includes the Oregon Institute of Technology, University of Arizona, University of Oregon, University of Texas at Arlington and University of Utah. We pursue our theme — improving mobility of people and goods to build strong communities — through research, education and technology transfer.

Portland State University researchers Martin Swobodzinski and Amy Parker, with student co-authors Julie Wright, Kyrsten Hansen and Becky Morton, have published a new article in Frontiers in Education: "Seamless Wayfinding by a Deafblind Adult on an Urban College Campus: A Case Study on Wayfinding Performance, Information Preferences, and Technology Requirements."

The article reports on an empirical evaluation of the experience, performance, and perception of a deafblind adult participant in an experimental case study on pedestrian travel in an urban environment. The case study assessed the degree of seamlessness of the wayfinding experience pertaining to routes that traverse both indoor and outdoor spaces under different modalities of technology-aided pedestrian travel. Specifically, an adult deafblind pedestrian traveler completed three indoor/outdoor routes on an urban college campus using three supplemental wayfinding support tools: a mobile application, written directions, and a tactile map.

Results indicate that wayfinding performance and confidence differed considerably between the three wayfinding support tools. The tactile map afforded the most successful wayfinding and highest confidence. Wayfinding performance and confidence were lowest for the mobile application modality.

The simplicity of use of a wayfinding tool is paramount for reducing cognitive load during wayfinding. In addition, information that does not match individual, user-specific information preferences and needs inhibits wayfinding performance. A substantial engagement of the deafblind community in both research and development is critical for achieving universal and equitable usability of mobile wayfinding technology.

Parker and Swobodzinski have partnered on two previous projects funded by the National Institute for Transportation and Communities (NITC), and this paper builds on findings from their research. The first project, A Comprehensive Examination of Electronic Wayfinding Technology for Visually Impaired Travelers in an Urban Environment, was completed in 2019 and provided an overview of existing mobile wayfinding technology as well as insights from focus groups with users. The second, Seamless Wayfinding by Individuals with Functional Disability in Indoor and Outdoor Spaces: An Investigation into Lived Experiences, Data Needs, and Technology Requirements, is in progress now.

Photo by Halfpoint/iStock

The Transportation Research and Education Center (TREC) at Portland State University is home to the National Institute for Transportation and Communities (NITC), the Initiative for Bicycle and Pedestrian Innovation (IBPI), and other transportation programs. TREC produces research and tools for transportation decision makers, develops K-12 curriculum to expand the diversity and capacity of the workforce, and engages students and professionals through education.

A new study launches next month, funded by the National Institute for Transportation and Communities (NITC). Researchers at Portland State University and the University of Texas at Arlington will explore the use of crowdsourced data to estimate pedestrian counts. The project team consists of Sirisha Kothuri and Nathan McNeil of Portland State University, and Kate Hyun and Stephen Mattingly of the University of Texas at Arlington. 

WHAT ARE PEDESTRIAN COUNTS USED FOR?

"You know that saying that if you can't measure it, you can't change it? For most streets, we might have some intuitive sense of if there are a lot of people walking there or not, but we rarely have data to back it. This project will assess how crowdsourced data can help to establish the level of pedestrian activity on streets throughout the transportation network," McNeil said.

Knowing how many pedestrians or bicyclists are using a link or a network is the foundation for measuring nonmotorized travel. Count data are useful for monitoring trends, planning new infrastructure, and for conducting safety, health, and economic analyses. The lack of widely available pedestrian count data precludes meaningful safety studies, which have become critically important, especially with the nationwide increase in pedestrian crashes over the last decade.

Several automated technologies have been developed to count bicyclists and pedestrians. Many advances in counting technology are more efficient than the old person-with-clipboard method, but cost and other considerations still limit direct observation to small subsets of entire networks. However, the emergence of crowdsourced data such as Strava and StreetLight has allowed for the collection of large-scale datasets over broad areas of the network. 

WHAT WILL BE STUDIED

While several research studies have evaluated and applied bicycle data from these datasets, no study has yet looked at pedestrian count estimates from these data sources or assessed how these compare to traditional pedestrian counts and other measures of pedestrian activity, such as pedestrian actuations from traffic signals. The researchers will evaluate pedestrian data estimates from the crowdsourced data sets and explore how these can be used along with traditional count data and sociodemographic data to derive count estimates.

"The lack of pedestrian counts limits our ability to conduct safety analyses, estimate changes in demand, determine where infrastructure improvements need to be made, and quantify the benefits of walking. We hope that the findings from the study can help agencies estimate pedestrian counts on their network and use them for a variety of applications," Kothuri said.

This project is one seven new research efforts funded by the latest General Research grant from NITC. Read about the other six projects here.

ABOUT THE PROJECT

Exploring the Use of Crowdsourced Data Sources for Pedestrian Count Estimations

Sirisha Kothuri and Nathan McNeil, Portland State University; Kate Hyun and Stephen Mattingly, University of Texas at Arlington

Photo by Dmytro Varavin/iStock

The Transportation Research and Education Center (TREC) at Portland State University is home to the National Institute for Transportation and Communities (NITC), the Initiative for Bicycle and Pedestrian Innovation (IBPI), and other transportation programs. TREC produces research and tools for transportation decision makers, develops K-12 curriculum to expand the diversity and capacity of the workforce, and engages students and professionals through education.

The 2021 World Symposium on Transport and Land Use Research was held virtually August–11, and three recorded sessions are available to watch. See below for links to the opening and closing keynote speeches and a panel discussion on Portland, Oregon's urban growth boundary. TREC co-sponsored the conference with The World Society for Transport and Land Use Research (WSTLUR). Portland State University's interim Associate Vice President for Research, Kelly Clifton, and TREC director Jennifer Dill co-hosted the event along with Yingling Fan of the University of Minnesota. Check out the recordings here:

The first WSTLUR symposium was held in Whistler, Canada 2011; the second was held in Delft, The Netherlands in 2014; and the third took place in Brisbane, Australia in 2017. This year's virtual conference was based out of Portland, Oregon and featured over 100 papers, with authors from 30 different countries around the globe.

The World Society for Transport and Land Use Research is the group that organizes the symposia and fulfills other aims of the Society. Its purpose as a society is to promote the interdisciplinary understanding of interactions between transport and land use and to provide a forum for debate and a mechanism for dissemination of research, while encouraging diverse viewpoints and backgrounds in our membership and activities.

The Transportation Research and Education Center (TREC) at Portland State University is home to the National Institute for Transportation and Communities (NITC), the Initiative for Bicycle and Pedestrian Innovation (IBPI), and other transportation programs. TREC produces research and tools for transportation decision makers, develops K-12 curriculum to expand the diversity and capacity of the workforce, and engages students and professionals through education.

If you could securely pick up your packages on your commute by public transit, from any carrier—be it USPS, FedEx, UPS or other companies, would you? Transit agencies could be missing a potential strategy to increase ridership by offering common carrier parcel lockers at transit facilities. 

Mitigating the demands on our urban transportation networks by consolidating parcel deliveries at high trafficked transit facilities could also benefit retailers, logistics and carrier companies, and consumers. But how do we ensure the equitable distribution of these sites for disadvantaged populations, while keeping accessibility in mind?

Using real world data from the Portland, OR region, a new study from researchers at Portland State University (PSU) offers a multiple-criteria approach using accessibility and equity metrics, including ridership, mode of transportation, spatial distribution, and sociodemographic profiles of coverage areas. 

Limited Free Access: The article in Transportation Research Record, "Accessibility and Equity Analysis of Transit Facility Sites for Common Carrier Parcel Lockers," by Katherine Keeling, Jaclyn Schaefer and Miguel Figliozzi, will be free to access for two months.

“There are multiple types of transit facilities that could work well as host sites for parcel lockers, but the accessibility and equity tradeoffs are complex,” shared Miguel Figliozzi, PSU engineering professor. “Transportation practitioners and policymakers have a lot to consider when prioritizing locations.”

Who could benefit from a common carrier parcel locker at transit facilities?

A lot of people stand to benefit from implementing common carrier parcel lockers at transit facilities: consumers, transit users, logistics and shipping companies, and the retailers.

If offered as a one-stop location for packages from different couriers, consumers could have the convenience of picking up multiple packages while getting on or off public transit. This is easily integrated into trip chaining–including spots near their home, workplace, or frequent errands. An added benefit is that an automatic/unmanned parcel locker system can offer 24-hour operations and more security than a porch drop-off.

Fragmentation and inefficient routing in delivery drives up the cost of last-mile logistics, especially to residential areas. Sometimes, older multi-unit complexes lack adequate space for receiving packages. Consolidation of multiple deliveries to one locker offers efficiencies of scale for delivery operations. Being less energy and time intensive, this could both lower carbon emissions and labor costs.

More efficient shipping options can reduce the costs that retailers absorb when they promote “free” shipping. Secure parcel lockers can also prevent profit losses due to order replacements or refunds to cover stolen packages.

Where do people ride transit, and is it accessible?

The ridership evaluation identified transit facilities with high levels of potential locker users. Researchers looked at a wide variety of transit facilities in Portland, OR–including: bus stops, light rail stops, bus + rail stops, transit center (bus only), transit center (bus + rail), park-and-rides (PaR), transit center + park-and-rides, and transit mall segments. 

Ultimately, the case study indicated that most of the high-ridership transit facilities are within the city center, where PaR facilities are absent. In fact, over half of the 20 highest ridership locations are segments of the downtown transit mall.

The accessibility by mode was extended not only to study equity issues but also because most research on transit-oriented lockers assumes that the catchment area for transit riders is constrained by the distance they are willing to walk with a parcel. However, transit riders that drive their personal vehicle to PaR facilities will not be inhibited by ‘‘willing to walk’’ estimates, and similarly, those who access transit via bicycle are not best represented by ‘‘willing to walk’’ estimates.

Keeping in mind the geometric design of the transit facility, consideration should be given to a loading/unloading zone that could accommodate heavy freight vehicles without interfering with transit activities. Turning radii and sight lines need to be safe for these delivery vehicles. Accessible design is also important for people with mobility impairments and/or and wheelchair users in the facility.

What method was used to determine equitable distribution of the parcel lockers?

“Immediately prior to this work, I had co-written a paper looking at the equity and environmental justice policy implications in home deliveries,” shared Figliozzi. “Disadvantaged groups are less likely to adopt home deliveries, and there are apparent barriers. That got me interested in considering how locating parcel lockers at transit facilities could potentially overcome some of those barriers.”

Some of the equity metrics they looked at included mode of transportation, population, where employers are located, and other key socioeconomic aspects (income, race, education level, and internet access). This was then compared among the twenty highest ridership transit facilities. 

The study demonstrated that there are complex tradeoffs between spatial coverage, type of facility, and equity metrics. There will always be budget constraints, and outside the scope of this research they must be considered alongside the design (and limitations) of the sites when looking at real-world implementation of lockers.

Implementing pilots at transit malls and suburban park-and-rides

Based on the data collected, a common carrier parcel locker system could take advantage of the high number of riders and foot traffic at the transit malls. It offers consolidated parcel collection points at the densest area of the city’s employment and transit networks. Another good option is at suburban PaR facilities which improves spatial equity and coverage, but also has the potential to serve a much greater population given the accessibility to drivers.

If cities and transit agencies are proactive in attracting public-private partnerships with delivery companies, a common carrier locker system could start with a pilot. Implementing a small number of locations and applying an equity-first approach would offer incremental growth of the program that is cost efficient, reaches a large population, and also covers areas serving disadvantaged populations.

Questions remain around how to best design accessible locker sites, and how to plan for the safety of parcel carriers and consumers. “Looking beyond the convenience of these parcel lockers, they should be considered when talking about the evolution of equitable transit-oriented development,” said Figliozzi. “This is one tool we could use in reducing the environmental impact of the last mile in freight delivery.”

About the Research

This article, “Accessibility and Equity Analysis of Transit Facility Sites for Common Carrier Parcel Lockers”, by Katherine Keeling, Jaclyn Schaefer, and Miguel A. Figliozzi and published in Transportation Research Record (TRR), will be free to access for a limited time.

Photo courtesy of TriMet

The research is funded by the Freight Mobility Research Institute––a U.S. DOT university transportation center. 

The Freight Mobility Research Institute (FMRI), housed in the Department of Civil, Environmental and Geomatics Engineering within FAU’s College of Engineering and Computer Science consists of a consortium of experts from universities across the nation with expertise in freight transportation, network modeling, sustainability, and intelligent transportation systems. http://eng.fau.edu/ 

Tags

We're proud to announce that Dr. Sirisha Kothuri, Senior Research Associate at Portland State University, has been awarded the 2021 Research Professional of the Year award by the Association of Pedestrian and Bicycle Professionals (APBP). The APBP Professional of the Year Awards recognize the achievements of pedestrian and bicycle professionals made in the last twelve months in the private, public, research, and nonprofit sectors.

Dr. Kothuri’s contributions to advance the state of practice in bicycle and pedestrian safety research are outstanding. She has worked to inspire the next generation in our field and advance the professional knowledge of others through research around multimodal traffic operations, bicycle and pedestrian counting, and safety, with an emphasis in innovation in non-motorized transport.

The Transportation Research and Education Center (TREC) at Portland State University is home to the National Institute for Transportation and Communities (NITC), the Initiative for Bicycle and Pedestrian Innovation (IBPI), and other transportation programs. TREC produces research and tools for transportation decision makers, develops K-12 curriculum to expand the diversity and capacity of the workforce, and engages students and professionals through education.

"Transformative Transportation Survey Methods: Enhancing Household Transportation Survey Methods for Hard-To-Reach Populations," is a new article published in the September 2021 issue of Transportation Research Part D. It was co-authored by Amy Lubitow, a sociology faculty member at Portland State University, Erika Carpenter, a sociology graduate student, and Julius McGee, a faculty member in urban studies and planning.

The study explores the challenges that hard-to-reach populations face in completing household activity surveys. Researchers drew on qualitative data from hard-to-reach populations regarding the limits of the Oregon Household Activity Survey and found evidence that the survey methods lack social, cultural, and linguistic applicability for Black, Indigenous and other people of color, as well as low-income populations. The authors argue that Oregon’s household travel survey prioritizes certain ways of understanding and experiencing mobility that are, by default, exclusionary. The article concludes in sharing insights regarding how transportation professionals might improve data collection efforts. Broader efforts for transportation equity (and ultimately towards transportation justice) cannot be achieved when the data used to inform transportation planning fails to accurately reflect all populations.

The paper draws on findings from a NITC research project led by Lubitow: Advancing Transportation Equity through Inclusive Travel Survey Data Methods

Photo by santypan/iStock

The National Institute for Transportation and Communities (NITC) is one of seven U.S. Department of Transportation national university transportation centers. NITC is a program of the Transportation Research and Education Center (TREC) at Portland State University. This PSU-led research partnership also includes the Oregon Institute of Technology, University of Arizona, University of Oregon, University of Texas at Arlington and University of Utah. We pursue our theme — improving mobility of people and goods to build strong communities — through research, education and technology transfer.

Projects
1122
Researchers
alubitow@pdx.edu

How can we use a variety of data-driven speed management strategies to make transportation safer and more efficient for all modes–whether you’re driving, walking or taking transit?

The project was led by Yao Jan Wu, director of the Smart Transportation Lab at the University of Arizona. Co-investigators were Xianfeng Terry Yang of the University of Utah, who researches traffic operations and modeling along with connected automated vehicles, and Sirisha Kothuri of Portland State University, whose research has focused on improving signal timing to better serve pedestrians. Join them on Sept 15, 2021 for a free webinar to learn more.

"We want to improve mobility for all users, be it pedestrians, vehicle drivers or transit riders, and there are different strategies to do this. How do we harness data to drive us to these strategies?" Kothuri said.

Funded by the National Institute for Transportation and Communities (NITC), this multi-university collaboration addressed the question from three angles:

  • Wu and his students in Arizona looked at the impact of speed management strategies on conventional roadways.
  • Yang and his team examined the effects of speed management strategies on connected corridors, coordinating with transit signal priority (TSP) systems.
  • Kothuri and her PSU team came up with an approach to estimate pedestrian delay at signalized intersections.

The aim of their combined research efforts was to investigate the possibility of developing and implementing more innovative speed management strategies that are effective for multimodal transportation and can be applied in both conventional roadways and "connected" roadways - i.e. equipped with vehicle-to-infrastructure or infrastructure-to-infrastructure communication capabilities.

IMPACT OF SPEED FEEDBACK SIGNS ON TRAFFIC FLOW AND SAFETY

Working with Pima County, Arizona, Wu and the Arizona research team evaluated the mobility and safety impacts of speed feedback signs on conventional roadways. Ina Road, a major signalized arterial in Tucson, was selected as the study corridor. This corridor was chosen because of the existing speed feedback signs along the corridor between signalized intersections, and due to the presence of advanced traffic data collection systems. Traffic data were collected for four weeks (May 28-June 25, 2018), and the existing signs were disabled for two weeks (June 11th-June 25th) during the data collection.

Using MioVision’s TrafficLink platform and high-resolution data, the researchers measured:

  • Percentage arrival on red: The percentage of vehicles that arrived at the intersection when the signal was red.
  • Split failure: The occurrence of leftover demand (when at least one vehicle in the queue was not able to go, but had to wait for the next green cycle) for a specific approach at an intersection.
  • Intersection delay: Total amount of time that all vehicles spend in the intersection queue while waiting to pass the intersection.

For a given time of day before and after disabling the speed feedback signs, only a little variation in traffic flow was observed. Similar traffic flow peaks for all the segments suggest that arterial mobility and traffic flow were not affected by disabling the signs. But what about the signs' effect on safety?

Data from the Pima Association of Governments show that the total number of severe crashes (four) on the study corridor all occurred before implementing the speed feedback signs in 2015. Moreover, using speed as a performance indicator, the researchers found a reduction in drivers' speeds along each link of the corridor, in between intersections (see page 21 of the final report for a table of speed results on weekdays and weekends). The reduction in the link speed was significant during the times the feedback signs were enabled, suggesting a reduced likelihood of severe crashes.

RETIMING SIGNALS FOR TRANSIT SIGNAL PRIORITY

Yang and the Utah team explored the impact of a speed management strategy on a connected corridor in Salt Lake City, Utah: how does signal retiming impact a transit signal priority (TSP) system?

Although TSP is a promising way to reduce bus delays at intersections, improve transit operational reliability, and consequently increase transit ridership with improved service, the effectiveness of TSP is subject to things like bus schedule, signal timing plan, passenger flows, etc. Considering this, the Utah Department of Transportation (UDOT) adopted a speed management strategy – signal coordination and retiming –  to improve the effectiveness of TSP. UDOT implemented signal coordination along a stretch of Redwood Road, a connected corridor with dedicated short-range communication, and applied several signal timing plans with the aim of maximizing the benefits of TSP. 

In general, researchers found, the average rate of TSP served before signal retiming was 33.13%, which is lower than that of 35.29% after signal retiming. This means that more buses requesting signal priority had their requests met, after the signals were retimed. In other words, the speed management strategies were also helping to improve bus reliability. 

In addition, bus travel time and bus running time were reduced after signal retiming. All of these findings indicate that the speed management strategy implemented along this connected vehicle corridor results in an improvement of TSP and bus service.

ESTIMATING PEDESTRIAN DELAY

There is technology, like signal controllers that can record high-resolution data, capable of recording pedestrian delay; but not every intersection is equipped with this technology because it is costly. Agencies are upgrading their infrastructure when possible, but there are still a lot of intersections where there is no means of knowing how long of a delay a pedestrian may experience. 

The PSU team, led by Kothuri, developed an alternative method for estimating pedestrian delay by using controller data for estimating multimodal signal performance measures.

Traditionally, signal timing is calibrated to prioritize vehicle movement, and long delays for pedestrians can increase noncompliance, causing unnecessary risk. So the team's goal was to find a way to use data to estimate what the pedestrian delay would be, at intersections that are not equipped with the latest infrastructure. Researchers took data from Ina Road, the same study corridor in Pima County, Arizona used to evaluate speed management strategies, and used finite mixture modeling to model pedestrian delay. Results showed that their method was able to successfully model the delay fluctuations with less than 10% mean absolute error. This method can be applied to intersections with similar characteristics as the test intersections. So cities and agencies that do not have signal controllers to capture pedestrian delay can use this finite mixture modeling method to figure out where they need to apply strategies to reduce that delay. 

The application of the proposed method could be beneficial to transportation agencies in three capacities:

  1. providing a more reliable, robust, and accurate approach for estimating pedestrian delay at signalized intersections where sensors are not available to collect pedestrian delay;
  2. a tool for analyzing the risk of pedestrians violating the signal;
  3. calibrating a network-wide model for estimating pedestrian delay at all intersections without the need to use additional resources

OUTCOMES OF THE RESEARCH

An effective strategy for improving mobility needed to consider both motorized and non-motorized modes of transportation. The three main achievements of this project were:

  1. Evaluate the impact of speed management strategies along conventional arterials using smart sensor data;
  2. Understand the role of conventional speed management strategies in supporting connected arterials;
  3. Examine the possibility of using controller event-based data to estimate multimodal signal performance measures.

Improved multimodal speed management strategies foster a safer community that will, in turn, encourage more people to walk and bike. This project addressed data-driven multimodal speed management strategies for traditional corridors using traffic sensors, and for future evaluation of connected vehicle-based strategies. The project also strengthened relationships between the three universities and their local partners, including Pima County and the Utah DOT.

"This project highlighted the strong collaboration we have among the universities. Trying to find innovative solutions during the process tied our universities together, bringing local resources together as well," Wu said.

ABOUT THE PROJECT

Data-Driven Mobility Strategies for Multimodal Transportation

Yao-Jan Wu, University of Arizona; Xianfeng Yang, University of Utah; Sirisha Kothuri, Portland State University

This research was funded by the National Institute for Transportation and Communities, with additional support from Pima County Public Works Administration, Portland State University, University of Arizona, University of Utah, and Utah Department of Transportation.

RELATED RESEARCH

To learn more about this and other NITC research, sign up for our monthly research newsletter.

Photo by csfotoimages/iStock

The National Institute for Transportation and Communities (NITC) is one of seven U.S. Department of Transportation national university transportation centers. NITC is a program of the Transportation Research and Education Center (TREC) at Portland State University. This PSU-led research partnership also includes the Oregon Institute of Technology, University of Arizona, University of Oregon, University of Texas at Arlington and University of Utah. We pursue our theme — improving mobility of people and goods to build strong communities — through research, education and technology transfer.