Browsing by Author "Duhn, Melissa"
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Item Driver Comprehension of Flashing Yellow Arrows(Minnesota Department of Transportation, 2023-12) Davis, Gary A.; Stern, Raphael; Duhn, Melissa; Gao, JingruIn 2009, the FHWA's Manual on Uniform Traffic Control Devices (MUTCD) introduced the flashing yellow arrow (FYA) traffic signal as an alternative to circular green (CG) to indicate permitted left turns. The FYA is arguably a more intuitive indication that left turns are permitted but not protected and, in addition, the FYA signal heads can support time-of-day changes between protective and permissive left -turn phasing. In 2019, a Research Needs Statement stated that "Research is needed to examine driver comprehension of flashing yellow arrows in different light arrangements and the role of signage." Our objective in this project was to assess drivers' understanding of FYA signal indications and to see if the presence or absence of "Left Turn Yield" signs affect gap acceptance. This was accomplished by conducting an online survey of drivers regarding their understanding of FYA signals and by carrying out a field study of drivers' gap acceptance at a set of Twin Cities intersections.Item Evaluation of the Effectiveness of Stop Lines in Increasing the Safety of Stop-Controlled Intersections(Minnesota Department of Transportation, 2020-07) Duhn, Melissa; Dirks, Peter; Loutfi, Andrew; Hourdos, John; Davis, GaryStop lines are ubiquitous, but do they really impact intersection safety? Prior to this project, no long-term studies on intersection safety with stop lines had been completed. This project was developed with two parallel research efforts: a safety study and an observational study. The safety study was developed to address stop lines’ effects over the long term and used crash data from five cities’ stop-controlled intersections to perform regression and see if stop lines actually influenced safety. The observational study was developed to determine if stop lines have an effect on driver behavior at intersections and to look at where drivers were stopping. Video was collected at 16 different intersections before and after a stop line was painted. The safety study and observational study showed that stop lines did not have a significant impact on driver behavior or intersection safety, but other factors like speed limits and sight distance did. Implications for practice include carefully examining sight distance at the intended stopping point to ensure drivers have adequate sight distance in both directions. If sight distance is not adequate, moving the intended stop location or reconsidering whether the intersection should have signage -- stop or yield -- or be uncontrolled could yield better driver compliance and safety.Item Generating Traffic Information from Connected Vehicle V2V Basic Safety Messages(Minnesota Department of Transportation, 2021-03) Chen, Rongsheng; Levin, Michael; Hourdos, John; Duhn, MelissaBasic Safety Message (BSM) containing data about the vehicle's position, speed, and acceleration. Roadside receivers, RSUs, can capture BSM broadcasts and translate them into information about traffic conditions. If every vehicle is equipped with awareness, BSMs can be combined to calculate traffic flows, speeds, and densities. These three key parameters will be post-processed to obtain queue lengths and travel time estimates. The project team proposed a traffic state estimation algorithm using BSMs based on the Kalman filter technique. The algorithm's performance was tested with BSMs generated from several arterial in a microscopic simulation model and BSMs generated with radar data collected on freeway sections. Then the project team developed a traffic monitoring system to apply the algorithm to a large-scale network with different types of roads. In the system, computers could remotely access the online server to acquire BSMs and estimate traffic states in real-time.Item Guidance for Separated/Buffered Bike Lanes with Delineators(Minnesota Department of Transportation, 2021-05) Hourdos, John; Duhn, Melissa; Dirks, Peter; Lindsey, GregSeparated bicycle lanes (SBLs) are bicycle facilities that employ both paint and a vertical element as a buffer between vehicle traffic and bicycle traffic. In recent years, the installation of SBLs has increased in the U.S. as planners and engineers seek to reduce crash risk, increase safety and foster demand. In turn, public demand for these facilities has continued to grow. This project conducted a thorough literature search to identify knowledge gaps and aspects of design not addressed in depth in existing guides. In collaboration with the Local Road Research Board and MnDOT, the study identified which design elements were of the greatest local interest or missing from the guidance altogether. The identified subject areas were explored with the help of three major knowledge gathering approaches: interviews of industry professionals from local agencies currently operating SBLs, interviews with leading bicycle advocates representing the local cycling community, and an ambitious and lengthy online survey of people who cycle in Minnesota. As noted by several existing guidance documents and corroborated by the information collected and analyzed in this project, the SBL is one of the highest quality bikeway facilities available. This report adds to the existing guidance regarding the planning and operation of SBLs by refining the discussion and taking into account individual aspects of separate design elements and their implementation alternatives, as well as their influence and limitations on maintenance needs, especially in winter. The guidance identifies multiple considerations for each of the selected structural elements and maintenance considerations to inform the choices made during the design process.Item How Locals Need to Prepare for the Future of V2V/V2I Connected Vehicles(Minnesota Department of Transportation., 2019-08) Parikh, Gordon; Duhn, Melissa; Hourdos, JohnConnected and Automated Vehicles (CAVs) are expected to affect the foundations of transportation operations and roadway maintenance as they become more prevalent on the roadways. This report is an effort to address this complex subject for the various owners, agencies and stakeholders involved in traffic operations. It discusses the connected vehicle ecosystem and its background, potential CAV applications, types of communication and hardware required for CAV systems, and recommendations to local road owners. The report also includes a survey sent to local road owners to assess the current readiness of the transportation system for CAVs. Although it is too early to give specific recommendations, general guidance is provided for road owners to begin preparing for the future of CAVs.Item I-94 Connected Vehicles Testbed Operations and Maintenance(Center for Transportation Studies, University of Minnesota, 2019-06) Duhn, Melissa; Parikh, Gordon; Hourdos, JohnIn March 2017, the Connected Vehicle Testbed along I-94 went live. The original project was sponsored by the Roadway Safety Institute and built on the Minnesota Traffic Observatory's (MTO) existing field lab, also utilizing certain Minnesota Department of Transportation (MnDOT) infrastructure. The testbed originally consisted of seven stations, rooftop and roadside, capable of transmitting radar and video data collected from the roadway back to a database at the MTO for analysis, emulating what a future connected vehicle (CV) roadway will look like. This project funded maintenance and upgrades to the system, as well as movement of some stations due to construction on I-94. In addition, better visualization tools for reading the database were developed. The CV testbed is state-of-the-art, fully functional, and uniquely situated to attract freeway safety-oriented vehicle to infrastructure (V2I) and vehicle to vehicle (V2V) safety application development, implementation, and evaluation projects going forward.Item Maximizing Saint Paul Employment Assets: Connecting the Workforce with Job-Rich Sectors(Resilient Communities Project (RCP), University of Minnesota, 2020) Wu, Emma; Duhn, Melissa; Geitz, Madeline; Burckhardt, YolandaThis project was completed as part of a partnership between the City of Saint Paul, the Metropolitan Council, and the University of Minnesota’s Resilient Communities Project (http://www.rcp.umn.edu). The goal of this project was to identify policy and outreach strategies to better connect employers and residents. City of Saint Paul project lead Mike Richardson collaborated with students in Professor Dipali Mukhopadyay’s course, PA 5041: Qualitative Methods for Policy Analysts, to conduct interviews with residents to understand perceptions and experiences with workforce development programs and the impact of the pandemic on the job-seeking process. A final student report and presentation are available. A videorecording of the students' final presentation is also available at https://vimeo.com/492665737.Item Multi-modal wayfinding in St. Louis Park(2021-05-16) Benesh, Meredith; Duhn, Melissa; Emory, Katie; Hong, ChrisSt. Louis Park is home to many popular trails and parks, as well as shopping centers and other important community resources. It is important that residents and visitors understand how to access all the destinations St. Louis Park has to offer. A wayfinding system designed for the needs of pedestrians, cyclists and transit users in St. Louis Park will aid people in navigating the city. It can also increase people’s comfort level when using non-vehicular modes of transportation and can even encourage people to walk, bike or take the bus more often. This project, led by four Master’s of Urban and Regional Planning students at the University of Minnesota, provides St. Louis Park staff the background, engagement tools, key considerations, and program and cost estimates they need to implement a wayfinding system within the city. The project employs a Race Equity & Inclusion (REI) lens to ensure the wayfinding system benefits all residents and provides special consideration for BIPOC (Black, Indigenous and People of Color) communities.Item Multi-Modal Wayfinding in St. Louis Park(2021-05) Benesh, Meredith; Emory, Katie; Duhn, Melissa; Hong, ChrisSt. Louis Park is home to many popular trails and parks, as well as shopping centers and other important community resources. It is important that residents and visitors understand how to access all the destinations St. Louis Park has to offer. A wayfinding system designed for the needs of pedestrians, cyclists and transit users in St. Louis Park will aid people in navigating the city. It can also increase people’s comfort level when using non-vehicular modes of transportation and can even encourage people to walk, bike or take the bus more often. This project, led by four Master’s of Urban and Regional Planning students at the University of Minnesota, provides St. Louis Park staff the background, engagement tools, key considerations, and program and cost estimates they need to implement a wayfinding system within the city. The project employs a Race Equity & Inclusion (REI) lens to ensure the wayfinding system benefits all residents and provides special consideration for BIPOC (Black, Indigenous and People of Color) communities.Item Pedestrian Crossings and Safety on Four Anishinaabe Reservations in Minnesota(Minnesota Department of Transportation, 2020-11) Lindsey, Greg; Hourdos, John; Dirks, Peter; Duhn, Melissa; Qi, Yunlei; Singer-Berk, Lila; Petesch, MichaelThe Minnesota Department of Transportation (MnDOT) has identified Native American as one of six priority populations in the state that face disproportionate risks as pedestrians. This report summarizes results from observations of pedestrian crossing behaviors on four Anishinaabe reservations in northern Minnesota. The University of Minnesota Traffic Observatory (MTO) video-taped and classified pedestrian crossings at 10 intersections identified by Tribal transportation managers as high priority because of perceived risks. Across the intersections, pedestrian crossing volumes during daylight hours ranged from 3 per day to 136 per day. The percent of pedestrian crossings that involved interactions with vehicles ranged from 9% to 54%. Tribal transportation managers from the Bois Forte, Fond du Lac, Grand Portage, and Mille Lacs Bands, MnDOT, county engineers, and the investigators collaborated to identify countermeasures to address risks to pedestrians. Proposed countermeasures varied by intersection and included vegetation removal and line-of-sight improvements, new lighting, crosswalk improvements, Rectangular Rapid Flashing Beacons with advanced warning signs, ADA-compliant ramps, pedestrian education programs, realignment of intersections, and at one intersection a Pedestrian Hybrid Beacon. Prospects for implementation of countermeasures vary by intersection and reservation and are contingent on Tribal and transportation agency budgets, state and county plans for roadway improvements, and categorical grant programs such as Minnesota's Transportation Alternatives Program. Some countermeasures are being implemented, and MnDOT is extending the approach to additional reservations.Item Traffic Impacts of Bicycle Facilities(Minnesota Department of Transportation, 2017-06) Hourdos, John; Lehrke, Derek; Duhn, Melissa; Ermagun, Alireza; Singer-Berk, Lila; Lindsey, GregEngineers need information about interactions between vehicles and bicyclists to design efficient, safe transportation systems. This study involved a review of design guidelines for bicycle facilities, observation of bicycle-vehicle interactions at nine roadways with different types of bicycle facilities, analysis of results, and description of design implications. Facilities observed included buffered and striped bicycle lanes, sharrows, signed shared lanes, and shoulders of various widths. Driver behaviors were categorized as no change in trajectory, deviation within lane, encroachment into adjacent lane, completion of a passing maneuver, and queuing behind cyclists. Drivers on roadways with bicycle lanes were less likely to encroach into adjacent lanes, pass, or queue when interacting with cyclists than drivers on roadways with sharrows, signs designating shared lanes, or no bicycle facilities. Queueing behind cyclists, the most significant impact on vehicular traffic flows, generally was highest on roads with no facilities or shared facilities without marked lanes. Statistical modeling confirmed the descriptive results. Given an objective of increasing predictability of driver behavior, buffered or striped bicycle lanes offer advantages over other facilities. Sharrows may alert drivers to the presence of cyclists, but traffic impacts on roadways with sharrows may not differ significantly from roadways with no facilities. Signs indicating bicyclists may occupy lanes also may alert drivers to the presence of cyclists, but this study provided no evidence that interactions on roadways marked only with signs differ from roadways with no facilities. From the perspective of reducing potential traffic impacts, bicycle lanes are to be preferred over sharrows or signage.Item Work Zone Mapping and Tag Deployment System(Center for Transportation Studies, University of Minnesota, 2019-10) Parikh, Gordon; Duhn, Melissa; Loutfi, Andrew; Hourdos, JohnRoadway construction is an inevitable part of functional transportation infrastructure. However, work-zone incidents have increased overthe years. This report is the third part of an interdisciplinary project to improve driver safety in work zones. The first component was ahuman factors study, performed by Craig et al. (2017), determining the most effective way to alert drivers to work zones without disrupting driver behavior. The second component, by Liao (2019), sought to determine whether Bluetooth low-energy tags could be deployed in work zones to provide real-time updates to drivers’ mobile phones through an app. The third component, the Statewide Work Zone Information System (SWIS), establishes a real-time database of active work zones from the first advanced warning sign being placed to the time the crews pack up. SWIS uses beacons attached to traffic control devices, called assets, that send messages to a central cloud repository. From there, messages are processed, categorized into Projects, Traffic Control Plans, and Work Zones. SWIS continuouslyupdates based on asset messages it receives. Users can access SWIS through a web interface, to view active, past or future projects, plan aproject, or update existing projects. SWIS provides an online, real-time portal for storing, monitoring, and inspecting work zone traffic-control operations.