ETConvention Center, 207A

The Traffic Calming Effect of Delineated Bicycle Lanes
Hannah Younes, Rutgers University
Clinton Andrews, Rutgers University
Robert Noland, Rutgers University
Jiahao Xia, Rutgers University
Song Wen, Rutgers University
Wenwen Zhang, Rutgers University, New Brunswick
Leigh Ann Von Hagen, Rutgers University, New Brunswick
Dimitri Metaxas, Rutgers, The State University of New Jersey

Jie Gong, Rutgers UniversityWe analyze the effect of a bicycle lane on traffic speeds. Computer vision techniques are used to detect and classify the speed and trajectory of over 9,000 motor-vehicles at an intersection that was part of a pilot demonstration in which a bicycle lane was temporarily implemented. After controlling for direction, hourly traffic flow, and the behavior of the vehicle (i.e., free-flowing or stopped at a red light), we found that the effect of the delineator-protected bicycle lane (marked with traffic cones and plastic delineators) was associated with a 28% reduction in average maximum speeds and a 21% decrease in average speeds for vehicles turning right. For those going straight, a smaller reduction of up to 8% was observed. Traffic moving perpendicular to the bicycle lane experienced no decrease in speeds. Painted-only bike lanes were also associated with a small speed reduction of 11-15%, but solely for vehicles turning right. These findings suggest an important secondary benefit of bicycle lanes: by having a traffic calming effect, delineated bicycle lanes may decrease the risk and severity of crashes for pedestrians and other road users.

ETConvention Center, 146A

Racializing Roads: Are Police Traffic Stops Racially Biased?
Wenfei Xu, Cornell University
Michael Smart, Rutgers University
Nebiyou Tilahun, University of Illinois, Chicago
Sajad Askari, University of Illinois, Chicago
Zachary Dennis, The University of Sydney
David Levinson, The University of Sydney

This paper exploits the potential of GPS data sourced from mobile phones to estimate the racial composition of road users, leveraging data from their respective Census block group. The racial composition data was collected on a representative Thursday in 2020, encompassing approximately 46 million trips in each the City of New York and the Chicago Metropolitan regions. The research primarily focuses on the correlation between camera tickets and racial composition of drivers vs. police stops for traffic violations and the racial composition in these locations. The violation rate measured by cameras is generally proportional to the racial composition of road users on the links with cameras. However, Black drivers exhibit a significantly higher likelihood of being stopped for traffic violations on roads, irrespective of the proportion of White drivers present. The research observes that this correlation attenuates as the proportion of White drivers on the road increases. This study therefore presents an important contribution to understanding racial disparities in traffic violation stops, with implications for policy interventions and social justice reforms.

ETConvention Center, 151B

Do Engineering Instructors Teach Induced Travel? If Not, Why Not?
Kelcie Ralph, Rutgers University
Ellen White, State University of New York, ESF

Induced travel remains a hotly contested concept. To what extent do instructors discuss it in transportation engineering classrooms? What explains their pedagogical decisions? We interviewed 15 university instructors in transportation engineering programs. Our interviews reveal remarkable variation. While some instructors featured induced travel as a central theme of their course, others omitted the idea entirely. Instructors also varied in their willingness to critique engineering practice; some were largely uncritical while others critiqued extensively. In justifying their pedagogical decisions, instructors offered a range of overlapping concerns. Those who “believed” in induced travel but did not teach it often lacked expertise in the area and were uneasy teaching “soft” concepts. Because teaching was not prioritized at their institutions, these instructors struggled to overcome those challenges. Instructors also advanced pragmatic concerns about the need to prepare students for the Fundamentals of Engineering Exam and their future careers. Next, some instructors who were more skeptical of induced travel wondered whether seemingly new travel was instead shifted or simply the result of previously suppressed demand. These instructors argued that even if new travel was indeed induced, engineers still had a responsibility to accommodate it. Finally, the interviews revealed that the contested language of induced travel can lead parties to talk past each other. “Believers” and “skeptics” sometimes have more in common than initially thought. However, there are still profound disagreements—about induced travel, standard engineering practices, and indeed the very purpose of engineering. In these debates it will be essential to operate from a shared vocabulary.

ETConvention Center, Hall A, poster A332

Is Induced Travel Missing from Transportation Engineering Textbooks?
Kelcie Ralph, Rutgers University
Ellen White, State University of New York, ESF

Do transportation engineering textbooks introduce students to the concept of induced travel? To find out, we conducted a systematic review of seven textbooks. We find that coverage of induced travel is often incomplete. Some textbooks omitted the idea entirely and those that did include it offered only partial coverage. Textbooks either defined the term, indicated its expected magnitude, used the concept in a problem set, or described the implications for practice. However, no single textbook included all these essential elements. Beyond this, all textbooks placed a greater emphasis on accommodating demand rather than managing it. Textbooks offered an asymmetric portrayal of how drivers adjust to traffic conditions. They tended to emphasize that drivers avoid congested areas and de-emphasized that drivers are also attracted to uncongested routes. Based on our review, we offer five criteria for developing high-quality teaching materials on this topic. Teaching materials should: 1) clearly define induced travel and distinguish it from other terms, 2) indicate the magnitude of induced travel we can expect, 3) feature the concept in problem sets to be consistent with engineering’s signature pedagogy, 4) describe the implications of induced travel for engineering practice, and 5) introduce students to foundational debates about transportation policymaking.

ETConvention Center, Hall A, poster B767

Rider-Centric Insights into Cyclists’ Behavior and Perception: A Review of Eye-Tracking Device Instrumented Cycling Experiments
Shiyu Ma, Rutgers: Rutgers The State University of New Jersey
Wenwen Zhang, Rutgers University, New Brunswick

With improved portability and affordability, eye tracking devices have facilitated an expanding range of cycling experiments, offering valuable rider-centric insights into cycling gaze behaviors and perceptions. To the best of our knowledge, however, there is no comprehensive review of eye-tracking devices instrumented cycling experiments. This paper aims to bridge the gap with three key focuses: (i) summarizing the research objectives and factors of interest in these experiments, (ii) reviewing the designs of cycling experiments and the analysis of gaze data in relation to study objectives, and (iii) examining the findings of the experiments and identify areas for future research. A systematic review of three databases yielded twenty-two articles that met the inclusion criteria. Our review suggests that the most studied factors related to the built environment include types of bike facilities and pavement quality, and the most frequently examined human factors include types of smartphone distractions. The ecological validity and generalizability of studies have been enhanced through more realistic experimental settings and increased sample sizes. Researchers typically used general gaze metrics to evaluate the mental workload and stress levels of the cyclists, whereas gaze measurements related to Areas of Interest (AOI) were used to infer attention allocation, visual search patterns, and hazard detection. Several research limitations and gaps are discussed, suggesting further investigations into the understanding of fixation and attention, the evaluation of the robustness of gaze measurements, and the optimization of data analysis processes.

ETConvention Center, Hall A, poster B748

Powering Bikeshare in New York City: Does The Usage of E-Bikes Differ from Regular Bikes?
Yingning Xie, Rutgers University, New Brunswick
Michael Smart, Rutgers University
Robert Noland, Rutgers University

In this study we investigate trip patterns of shared electric bicycles (e-bikes) operated by CitiBike in New York City. We address two questions: 1) Are trip generation patterns different between e-bikes and classic bikes? 2) And are there differences in factors associated with trip generation, such as bike infrastructure, subway proximity, population, land use, and elevation? We use CitiBike trip data from September 2022 and evaluate trip patterns and estimate a spatial regression model. The percentage of e-bike trips fluctuates across hours of a day, with a peak around 3PM but diminishes during peak hours. We find mostly no significant differences in factors associated with the generation of trips between the two modes. Exceptions include a larger effect on e-bike trip generation when the daytime worker population is larger; other differences are due to the racial composition around the station area, some land use categories, and elevation differentials.

ETConvention Center, 146C

Gender Split and Safety Behavior of Cyclists and E-Scooter Users in Asbury Park, New Jersey
Hannah Younes, Rutgers University
Robert Noland, Rutgers University
Clinton Andrews, Rutgers University

Micromobility usage has increased significantly in the last several years as exemplified by shared e-scooters and privately owned bicycles. We use traffic camera footage to observe the behavior of over 700 shared e-scooters and privately owned bicycles in Asbury Park, New Jersey. The following questions are addressed: (1) What are the behavioral differences between bicycle and e-scooter usage in terms of helmet use, bike lane / sidewalk use, gender split, group riding, and by time of day? (2) Are more protective conditions associated with helmet use and bike lane / sidewalk use? And (3) what is the gender split between e-scooter users and cyclists? We find notable differences in safety precautions: around one third of cyclists but no shared e-scooter users were observed wearing a helmet. Among cyclists, helmet use was more prominent among men than women. However, men were more likely to ride on the road than women. We also found that the gender split was narrower among e-scooter users, with a nearly even gender split – as opposed to cyclists, where only 21% of cyclists were observed to be women. Our findings suggest that e-scooter users take fewer safety precautions, in that they are less likely to use a bike lane and to wear a helmet. We conclude with policy implications with regards to safety and gender differences between these two modes.