The Influence of Bike Lane Buffer Types on Perceived Comfort and Safety of Bicyclists and Potential Bicyclists

Buffered and protected bike lanes are increasingly recognized as a valuable tool in enticing potential or wary cyclists to use a bicycle for transportation. These facilities— which provide extra space and (in the case of protected bike lanes) physical separation from motor vehicles—have been studied and are preferred by many bicyclists over traditional bike lanes. There has been little research, however, on the difference between buffer types and how they impact people’s sense of the safety and comfort of bicycling. This paper uses data from surveys collected for a multi-city study of newly constructed protected bike lanes to examine the influence of various hypothetical and actual buffered bike lane designs (some with and some without physical protection) from the perspective of current bicyclists (n=1,111) and residents living near the new facilities (n=2,283) who could be potential bicyclists. Findings suggest striped or painted buffers offer some level of increased comfort, while buffers with some sort of physical protection, even as minimal as a plastic flexpost, yield significant increases in perceived comfort for potential cyclists with safety concerns (the Interested but Concerned demographic). Among residents living near recently built protected bike lanes, 71% of all residents and 88% of the Interested but Concerned indicated that they would be more likely to ride a bicycle if motor vehicles and bicycles were physically separated by a barrier

Calibrating the HSM Predictive Methods for Oregon Highways

The Highway Safety Manual (HSM) was published by the American Association of State Highway and Transportation Officials (AASHTO) in the spring of 2010. Volume 2 (Part C) of the HSM includes safety predictive methods which can be used to quantitatively estimate the safety of a transportation facility. The resulting information can then be used to provide guidelines to identify opportunities to improve transportation safety. The safety performance functions (SPFs) included with this content, however, were developed for several states other than Oregon. Because there are differences in crash reporting procedures, driver population, animal populations, and weather conditions (to name a few), the State of Oregon needs to use calibrated SPFs when applying the HSM procedures to local Oregon facilities. Currently, the predictive methods have been developed for three facility types: rural two-lane two-way roads, rural multilane roads, and urban and suburban arterial roads. In this project, the research team calibrated SPFs for all three facility types based on their historic safety performance in Oregon. The report illustrates methods of site selection, the collection of crash and site-specific data, and analysis methods for calibration. Also, the report includes an evaluation of the crash severity distribution methods. With this information, Oregon agencies can use the calibrated HSM predictive methods to assess expected facility safety performance for Oregon conditions and facility alternatives

Evaluation of Bike Boxes at Signalized Intersections [Presentation]

A presentation summarizing findings of a study on the effectiveness of bike boxes at signalized intersections. Presentation delivered to the Association of Collegiate Schools of Planning Conference in Minneapolis, MN, Oct. 7-10, 2010

Multimodal Data at Signalized Intersections: Strategies for Archiving Existing and New Data Streams to Support Operations and Planning & Fusion and Integration of Arterial Performance Data

There is a growing interest in arterial system management due to the increasing amount of travel on arterials and a growing emphasis on multimodal transportation. The benefits of archiving arterial-related data are numerous. This research report describes our efforts to assemble and develop a multimodal archive for the Portland-Vancouver region. There is coverage of data sources from all modes in the metropolitan region; however, the preliminary nature of the archiving process means that some of the data are incomplete and samples. The arterial data sources available in the Portland-Vancouver region and that are covered in this report include data for various local agencies (City of Portland, Clark County, WA, TriMet and C-TRAN) covering vehicle, transit, pedestrian, and bicycle modes. We provide detailed descriptions of each data source and a spatial and temporal classification. The report describes the conceptual framework for an archive and the data collection and archival process, including the process for extracting the data from the agency systems and transferring these data to our multimodal database. Data can be made more useful though the use of improved visualization techniques. Thus as part of the project, a number of novel, online visualizations were created and implemented. These graphs and displays are summarized in this report and example visualizations are shown. As with any automated sensor system, data quality and completeness is an important issue and the challenge of automating data quality is large. Preliminary efforts to validate and monitor data quality and automate data quality processing are explored. Finally, the report presents efforts to combine transit and travel time data and signal timing and vehicle count data to generate some sample congestion measures

Safest Placement for Crosswalks at Intersections

This research studied the relationship between crosswalk setback and intersection safety. The study included field-based and driving simulator experiments. Video data was collected at 10 crosswalks in Oregon to examine the frequency pedestrian-vehicle conflicts (measured using PET), including how these conflicts vary between corner and setback crosswalks. A total of 507 pedestrians and 47 conflicts with post-encroachment times of less than 5 seconds were observed. The 50 participants driving simulator experiment was used to determine how setback distances, curb radii, and presence of pedestrians affect driver stopping decision and position, speed choice, visual attention, and level of stress. Observations of drivers\u2019 speed in a similar scenario were taken from field and simulator data to enhance the evidence provided by each experiment. Stop line speeds were found to be consistent between experiments and turning speeds were found to be slightly higher in the driving simulator experiment. The study results suggest that curb radius should be smaller to control driver speed. Additionally, setback distance of the crosswalk of 20ft is a suitable upper bound when reconstructing intersections

Quantifying the Performance of Low-Noise Rumble Strips

SPR 800Shoulder or centerline rumble strips (RS) generate noise and vibration to alert drivers when they are departing the lane of travel. Although inexpensive to install, easy to maintain, and very long-lasting, RS are not installed on many roadway segments primarily due to noise concerns of nearby property owners. This study evaluated the feasibility of using sinusoidal RS as a substitute for rounded milled RS on roadway segments in Oregon with lane-departure crash problems. Exterior and interior sound levels and interior vibrations generated by rounded and sinusoidal RS strikes were compared to baseline and no-strike sound levels for 3 vehicle classes (passenger car, van, and heavy vehicle) to establish sound generation and alerts of the 2 designs. A total of 114 vehicle strikes of RS were recorded. Rumble strip strikes by the passenger car and van generated less exterior noise with the sinusoidal than with the rounded design. Interior noise generated by striking the sinusoidal design generated a clearly noticeable alert, suggesting that the sinusoidal rumble strip is still an effective countermeasure. Based on thresholds of human perception for vibration, both rumble strip types generated sufficient vibration to alert the driver. Results for the heavy vehicle were complicated due to bridging of the harrower rounded rumble strip by the tires. The wider cut of the sinusoidal RS generated a clearly detectable increase in exterior roadside noise for the Heavy Vehicle. Likewise, the sinusoidal design created a noticeable interior alert for the HV but the rounded design did not

Development, Deployment, and Assessment of a New Educational Paradigm for Transportation Professionals and University Students

Traditionally, engineering coursework has been delivered in a lecture-based format with accompanying exercises assigned for time outside of class. The activity-based approach to learning aims to keep students engaged in and responsible for their own learning processes. This approach has been shown to be more effective than conventional teaching approaches in terms of long-term retention of the educational material

Empirical Observation of the Impact of Traffic Oscillations on Freeway Safety

Traffic oscillations are typical features of congested traffic flow that are characterized by recurring decelerations followed by accelerations (stop-and-go driving). The negative environmental impacts of these oscillations are widely accepted, but their impact on traffic safety has been debated. This report describes the impact of freeway traffic oscillations on traffic safety. This study employs a matched case-control design using high resolution traffic and crash data from a freeway segment. Traffic conditions prior to each crash were taken as cases, while traffic conditions during the same periods on days without crashes were taken as controls. These were also matched by presence of congestion, geometry and weather. A total of 82 cases and about 80,000 candidate controls were extracted from more than three years of data from 2004 to 2007. Conditional logistic regression models were developed based on the case-control samples. To verify consistency in the results, 20 different sets of controls were randomly extracted from the candidate pool. The results reveal that the standard deviation of speed (thus, oscillations) is a significant variable, with an average odds ratio of about 1.08. This implies that the odds of a (rearend) crash occurring increases by about 8 percent with an additional unit increase in the standard deviation of speed. The average traffic states prior to crashes were less significant than the speed variations in congestion

Tracking Trucks to Improve Performance

Freight transportation is an important part of Oregon’s economy, and the Oregon Department of Transportation, or ODOT, continually observes the highway system to make sure it is running as smoothly as possible. By monitoring the progress of individual trucks, ODOT can obtain performance metrics such as travel time, travel delays, and origin-destination flows. This information can help identify slow passages or bottlenecks in the highway system. Typical ways of obtaining these metrics, however, may involve purchasing expensive equipment, and may also raise privacy concerns if each truck is required to carry a tracking unit. To avoid these difficulties, Portland State University researcher Chris Monsere explored a simpler way to get freight performance measures using a probabilistic approach

Exploratory Methods for Truck Re-Identification in a Statewide Network Based on Axle Weight and Axle Spacing Data to Enhance Freight Metrics: Phase II

Vehicle re-identification methods can be used to anonymously match vehicles crossing two different locations based on vehicle attribute data. This research builds upon a previous study and investigates different methods for solving the re-identification problem and explores some of the factors that impact the accuracy of the results. To support this work, archived data from weigh-in-motion (WIM) stations in Oregon are used for developing, calibrating, and testing vehicle re-identification algorithms. In addition to the Bayesian approach developed by the researchers in the previous study, a neural network model is developed for solving the re-identification problem. The results from the testing datasets showed that both methods can be effective in solving the re-identification problem while the Bayesian method yields more accurate results. A comprehensive analysis is performed to investigate the key factors impacting the accuracy of the results. The analyses are performed by employing the Bayesian algorithm to match commercial vehicles that cross upstream and downstream pairs of WIM sites that are separated by long distances ranging from 70 to 214 miles. Data from 14 different pairs of WIM sites are used to evaluate how matching accuracy is impacted by various factors such as the distance between two sites, travel time variability, truck volumes, and sensor accuracy or consistency of measurements. After running the vehicle re-identification algorithm for each one of these 14 pairs of sites, the matching error rates are reported. The results from the testing datasets showed a large variation in terms of accuracy. It is found that sensor accuracy and volumes have the greatest impacts on matching accuracy whereas the distance alone does not have a significant impact. Overall, for estimating travel times and origin-destination flows between two WIM sites, the methods developed in this project can be used to effectively match commercial vehicles crossing two data collection sites that are separated by long distances