Driver and Bicyclist Comprehension of Blue Light Detection Confirmation Systems

This study analyzed motorist and bicyclist understanding and preference of positive confirmation of detection of a bicycle by the traffic signal infrastructure using a blue light detection confirmation (BLDC). The research analyzed results of an online survey of 1,123 respondents and intercept survey of 337 respondents. The study initially found that participants of the survey did not understand the meaning of the blue light itself, but comprehension of the system rose from 40% to 50% when supplemental signs were used. Respondents overwhelmingly indicated that they preferred the sign option that included symbols, text, and a representation of the blue light, in comparison with the sign options that only included symbol and text, or text and blue dot. Additionally, respondents indicated that they “strongly agree” that the supplemental signage helped with understanding the purpose of the detection confirmation devices, that they would support the system at intersections, and that it made them feel better about waiting at an intersection with light. Including supplemental signage with the symbol, text, and blue dot could potentially improve the riding experience for users, as it was strongly preferred among the alternative sign options that were tested; however, further evaluation of sign configurations may be warranted

Measuring pedestrian level of stress in urban environments: Naturalistic walking pilot study

Walking is the most basic and sustainable mode of transportation, and many jurisdictions would like to see increased walking rates as a way of reducing congestion and emission levels and improving public health. In the United States, walking trips account for 10.5% of all trips undertaken. To increase this rate, additional research on what makes people feel more comfortable while walking is needed. Research on pedestrian quality of service (QOS) has sought to quantify the performance of the pedestrian facilities from a pedestrian’s perspective. However, the impact of pedestrian safety countermeasures on pedestrian QOS for roadway crossings is largely unknown. The objective of this study is to discern pedestrian QOS based on physiological measurements of pedestrians performing normal walking activities in different traffic contexts. The naturalistic walking study described in this paper recruited 15 pedestrians and asked each to wear an instrumented wristband and GPS recorder on all walking trips for one week. Surprisingly, the findings from the study showed no correlation between participants’ stress levels and individual crossing locations. Instead, stress was associated with roadway conditions. Higher levels of stress were generally associated with walking in proximity to collector and arterial streets and in areas with industrial and mixed (e.g., offices, retail, residential) land uses. Stress levels were tempered in lower-density residential land uses, as well as in forest, park, and university campus environments. The outcomes from this study can inform how planners design urban environments that reduce pedestrian stress levels to promote walkability

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

An Assessment of Bicycle Detection Confirmation and Countdown Devices

For a person on a bicycle at intersections, trail crossings, or midblock locations that are signalized, knowing that they have been detected and how long they must wait to receive a green indication is valuable information. This presentation will summarize the findings from the online survey (1,048 responses), observed behaviors (2,428 persons on bicycle), and an intercept survey ( 234 persons) to understand blue light feedback devices and countdown timers at signalized intersections. Findings suggest that the design where the blue light was embedded in the sign was more visible to cyclists and observed by higher proportions of cyclists in the field. Results show that a bicycle signal countdown timer elicited high comprehension rates. At all locations, cyclists indicated that the devices improved their waiting experience.https://pdxscholar.library.pdx.edu/trec_seminar/1209/thumbnail.jp

Evaluation of Driver Comprehension and Visual Attention of the Flashing Yellow Arrow Display for Permissive Right Turns

This research explored driver comprehension and behaviors in Oregon with respect to right-turn signal displays focusing on the Flashing Yellow Arrow (FYA) in a driving simulator. A counterbalanced, factorial design was chosen to explore three independent variables: signal indication type and active display, length of the right-turn bay, and presence of pedestrians. Driver decision-making and visual attention were considered. Data were obtained from 46 participants (21 women, 25 men) turning right 736 times in 16 experimental scenarios. A Mixed-effects Ordered Probit Model and a Linear mixed model were used to examine the influence of driver demographics on observed performance. Results suggest that the FYA indication improves driver comprehension and behavioral responses to the permissive right-turn condition. When presented with the FYA indication in the presence of pedestrians, nearly all drivers exhibited caution while turning and yielding to pedestrians and stopping when necessary. For the same turning maneuver, drivers presented with a circular green (CG) indication were less likely to exhibit correct behavior. At least for Oregon drivers, another clear finding was a general lack of understanding of the steady red arrow (SRA) display for right turns. Most drivers assume the SRA indication requires a different response than the circular red (CR) and remain stopped during the entire red interval, thus resulting in efficiency losses. These findings suggest that transportation agencies could potentially improve driver yielding behavior and pedestrian safety at signalized intersections with high volumes of permissive right turns from exclusive right-turn lanes by using the FYA display in lieu of a steady CG displa

Systemic Opportunities to Improve Older Pedestrian Safety: Merging Crash Data Analysis and a Stakeholder Workshop

This paper presents a framework for improving older pedestrian safety in regard to serious (fatal and incapacitating) crashes, using Oregon as a case study. On review of state and federal practices pertaining to older pedestrian safety, 4 years of crash data identified 112 older (≥ 65 years) pedestrian serious injury crashes. These data were explored for factors that might be addressed systemically using two methods. First, raw frequencies in the crash data were assessed to determine trends and crash-related factors that are overrepresented. Second, a random forest analysis was conducted to determine important variables for predicting older pedestrian serious injury crashes. Using these crash-related factors, a workshop was held with 18 local stakeholders and experts. As part of the workshop, key crash trends, potential causations, and potential countermeasures by priority of implementation were determined based on perspectives from workshop participants. Three key systemic solutions were identified to improve older pedestrian safety, including improving pedestrian visibility and illumination, implementing treatments for left turns, and shortening pedestrian crossing distances across the state. The framework presented in the current study could be adopted by other agencies to systemically address a wide variety of safety concerns

Do Drivers Correctly Interpret the Solid Circular Green from an Exclusive Right-Turn Bay?

In 2016, the U.S. recorded the highest number of pedestrian fatalities since 1990. Turning vehicles pose a collision risk for non-motorized road users. To improve traffic safety and efficiency at signalized intersections, driver behavior associated with right-of-way transitions at signalized intersections must be understood more comprehensively. This study explored the safety concern of driver’s potential to incorrectly interpret the solid circular green (SCG) during right-turns using a high-fidelity driving simulator. A counter-balanced, factorial design was chosen to explore two independent variables: signal indication type and presence of a pedestrian. The pre-turn speed, visual attention and driver decision making were used as performance measures. Data were obtained from 46 participants (21 women) turning right 184 times in 4 experimental scenarios. Two linear mixed effects models and a frequency analysis were used to examine within-subject variables on observed performance. Results from both the frequency analysis and the statistical model suggest that for the same turning maneuver, drivers presented a SCG were less likely to exhibit correct behavior. While drivers had similar speed for both the SCG and solid green arrow (SGA) signals, drivers fixated on the SGA head longer. The similar speed indicates that drivers are interpreting the SCG as a protected indication. When presented with the SCG indication in the presence of pedestrians, 33% of drivers exhibited improper behavior while turning right, resulting in a situation with high crash potential. For the same turning maneuver, drivers presented with SGA indication were more likely to exhibit correct behavior. This indicates that SGA can promote a safer interaction between right turning vehicles and pedestrians in the conflicting crosswalk. These findings provide quantitative data that could be used by transportation agencies to improve driver comprehension and pedestrian safety at signalized intersections

Use of Data from Point Detectors and Automatic Vehicle Identification to Compare Instantaneous and Experienced Travel Times

Most tratlic management centers use detector data to estimate instantaneous travel times. Interest is increasing in using automatic vehicle identification (AVI) readers to provide travel time measurements as well as in using predictive modeling of travel times. This study aimed to examine the differences between travel time estimation that was based on detector data versus those based on AVI data. In addition, the study compared instantaneous travel time estimates with experienced travel time estimates to determine the adequacy of disseminated instantaneous travel time information and, thus, the potential benefits of using predictive travel time modeling. The results showed that, for uncongested conditions, the difference between point detector- and AVI-based estimates and between instantaneous and experienced travel times was insignificant. During congested traffic conditions, the difference between estimates based on detector data and those based on AVI data (Bluetooth and electronic toll tag reader data) was about 6% to 17%. In addition, a difference of 10% to 20% existed between instantaneous and experienced travel times estimated from both the detector data and AVI data; this difference depended on the tested scenarios. The values of the differences between instantaneous and experienced travel times from both types of data sources are expected to be affected by the queue-forming and -dissipating speeds, route length, and the location of the congestion

Assessing the Impact of Three Intersection Treatments on Bicyclist Safety Using a Bicycling Simulator.

Bicyclist safety at urban intersections is a critical element for encouraging an increase in bicycle commuting. With cyclist injury and fatality rates rising due to collisions with vehicles at signalized intersections, increasing the safety of riders continues to be an important consideration when promoting this mode of transportation. Previous research has addressed crash causality and helped to develop several roadway treatments to improve bicyclist safety, but little has been done to compare and contrast the benefits of the various treatment types. This bicycling simulator study examined the impacts of three different intersection treatments (i.e., bike box, mixing zone, and bicycle signals) to better understand their influence on bicyclists\u27 comfort, levels of stress, and riding behaviors. This improved understanding allowed researchers to make recommendations for which of the three designs proved to be most effective for reducing the risk of vehicle-bicycle collisions at signalized intersections. Forty participants successfully completed the study by responding to twenty-four scenarios while riding in the Oregon State University Bicycling Simulator. Time-space measurements revealed that the mixing zone treatment correlated with the most unpredictable riding behaviors. Analysis of the participants\u27 eye-movements revealed a lower rate of recognizing the conflict vehicle when traversing the bicycle signal treatments. Galvanic Skin Response measurements were used to measure participants stress levels but found no statistically significant results, although it was found that the mixing zone elicited slightly larger stress responses. Researchers found the bike box design to be the most versatile, providing a balance of increased safety while also requiring the participant to perceive potential danger and be ready to respond accordingly. The results of this research can provide a better understanding of how to best implement these intersection treatments to increase bicyclists\u27 safety at signalized intersections

User Comprehension of Bicycle Signal Countdown Timers

For a person on a bicycle at signalized intersections, trail crossings, or midblock locations, knowing how long they must wait to receive a green indication is valuable information. In the international context, this information is often provided by small, nearside bicycle signal heads that contain a countdown display that visually conveys the amount of waiting time. This paper presents the results of research to investigate the comprehension of bicycle countdown timer displays in the U.S. context. The study conducted an online survey to analyze the understanding and preference of three alternative bicycle countdown timer displays. Respondents were recruited by two recruitment methods: mailed postcards (568 responses) and social media ads (772 responses). A countdown timer with circular disappearing dots was then installed at an intersection in Portland, OR, and an intercept survey was conducted of users (29 responses). For both surveys, comprehension rates were established by coding an open-ended response to a question about the display\u27s intended meaning. The surveys found that the bicycle signal countdown displays were intuitive, and the intended meaning was fully understood by over 60% of online survey respondents and 52% of the intercepted bicyclists. Partial comprehension increased to over 70% and 97% of those intercepted, respectively, which would result in safe user interpretation. A countdown timer may also improve the waiting experience for stopped bicyclists, as 70% of respondents strongly or somewhat agreed that they would feel better about waiting at an intersection if a bicycle countdown timer was present