SafeTREC at TRB 2013
SafeTREC students, faculty and researchers are participating in numerous events at the 2013 Annual Meeting of the Transportation Research Board, January 13-17, 2013 in Washington, D.C. Their presentations are listed below in chronological order.
Download the SafeTREC at TRB 2013 flyer with the schedule here.
Share your experiences at the TRB Annual Meeting on Twitter, #TRBAM and follow SafeTREC @transsafe.
Monday, January 14, 2013
"Roadway and Infrastructure Design and Its Relation to Pedestrian and Bicyclist Safety: Basic Principles, Applications, and Benefits" 13-4820
David R. Ragland, Offer Grembek, Phyllis Orrick, Grace Felschundneff, SafeTREC, University of California, Berkeley
Road deaths are forecast to double by 2020, with the burden falling most heavily on low- and middle-income countries and, within those countries, on the most vulnerable and poorest road users. Half of the 1.2 million people killed and 50 million injured in road crashes each year are pedestrians, motorcyclists, bicyclists, and users of unsafe public transport; and more than 90 percent are from low- and middle-income countries. Because these are the areas where rapid motorization is taking place, the issue of safety in increasingly multi-modal environments is now of critical importance, particularly for pedestrians and bicyclists, since as vulnerable road users (VRU), they comprise a large proportion of injuries and deaths, and similar strategies for prevention of injuries and fatalities for these two groups are available. Although a great deal of additional research is needed to determine the costs and benefits of various proposed solutions, some basic principles can be identified to guide roadway and infrastructure design for improved pedestrian and bicyclist safety. The three broad but separate strategies for reducing the probability of an injury or fatality are: (i) reducing exposure, (ii) reducing the probability of a collision given exposure, and (iii) reducing the probability of injury given a collision. The purpose of this paper is to describe and illustrate these principles, discuss issues related to each one, and discuss the benefits—indeed, imperativeness—of the application of these principles by planners and traffic engineers.
Session 222 - Safety Implications of Highway Geometric Designs
Monday, January 14, 2013 8:00AM - 9:45AM
Shoreham, Ambassador
Lectern Session
"Low Cost Upgrades to At-Grade Crossing Safety Devices" 13-4164 practice-ready paper
Douglas L. Cooper, David R. Ragland, Grace Felschundneff, SafeTREC, University of California, Berkeley
The only way to absolutely prevent all drivers from going around lowered gates at level rail-highway crossings is to make it physically impossible, or at least very difficult, for them to do so. While there are various options to accomplish this (constructing a separation of grade, closing the crossing, or deploying an impenetrable concrete barrier), most have high monetary or social costs. Alternative approaches—such as channelization devices and long-arm gates—while not 100 percent effective, can be used to prevent deaths and injuries while remaining economically feasible. Research has shown that the addition of channelization devices can dramatically reduce the number of violations at level rail-highway crossings. While long-arm gates appear to be effective, additional study is needed to determine their suitability for individual locations. Unfortunately, even when overall rail crash totals for the country or for a given state are high, crashes at specific crossings are relatively rare events, making it extremely difficult to show that the addition of a safety treatment at a particular site prevented a crash. However, based on the efficacy of channelization devices—75 percent—in addition to the experiences of various transportation agencies, these devices appear to be a viable, low cost safety upgrade for at-grade crossings.
Session 338 - Highway-Rail Grade Crossing Safety Options
Monday, January 14, 2013, 2:00PM - 3:45PM
Marriott, Salon 2
Poster Session
"Weighing Integration by Block Heterogeneity to Evaluate Pedestrian Activity" 13-0579
Offer Grembek, SafeTREC, University of California, Berkeley; Minh-Tan Do, French Institute of Science and Technology for Transport, Development and Networks; David R. Ragland, Ching-Yao Chan, SafeTREC, University of California, Berkeley
Pedestrian exposure is a necessary component for a meaningful evaluation of pedestrian safety. The Space Syntax approach has a track record of accurate prediction of pedestrian activity, by estimating the physical street connectivity in urban environments. However, for some environments, the performance of Space Syntax is limited and cannot be used as a reliable estimate of exposure. This paper makes use of the interdependency between: (i) street connectivity - estimated here using integration; and (ii) land-use characteristics; to propose a mechanism to adjust integration by land-use features at the block level. Values of integration for each street-block, which hold the same mean values along the same street, are weighted based on dominant land-use features. The weighted integration value for a street-block dominated by commercial property is higher than the mean integration value for that street. Conversely, the weighted integration value for a residential street-block is lower than the mean integration value for that street. The proposed approach captures the heterogeneity of street-blocks, which is not always captured by Space Syntax. Applying this method to the northern periphery of the University of California, Berkeley, has produced promising preliminary results. It was shown that the weighted integration values (at the street-block level) are better correlated with pedestrian volumes than mean integration values (street scale). Further research efforts are required to develop this simplified approach into a pedestrian exposure prediction model.
Session 340 Pedestrian Planning, Policy, and Demand Analysis
Monday, January 14, 2013 2:00PM - 3:45PM
Marriott, Salon 2
Poster Session | Practice Ready Papers
"Missed or Delayed Medical Care Appointments by Older Users of Nonemergency Medical Transportation Services" 13-2879
Kara E. MacLeod, David R. Ragland, SafeTREC, University of California, Berkeley; Thomas R. Prohaska, George Mason University; Cheryl Irmiter, American Medical Association; William Satariano, University of California, Berkeley; Mary A. Leary, Easter Seals Transportation Group
Non-emergency medical transportation (NEMT) can prevent emergency care as a result of delayed or missed medical appointments. Medicaid provides NEMT for low income individuals who have no other means of transportation and this is a critical component of the health care delivery system. This study examined cancelled trips in Medicaid adults age 65+ to explore whether barriers persist for a growing segment of the population who face particular challenges of age-related declines in health and function. Multivariate logistic regression analyses were conducted using transportation brokerage data for Delaware members who intended to travel during 2008-2010, modeling the odds of all cancellations and then these mutually exclusive types: (1) client cancelled; (2) client obtained alternative transportation; and (3) client cancelled due to health. Over half of the cancelled trips were attributed to client reasons. Black race was associated with client canceling (OR=1.4) and canceling due to alternative transportation (OR=1.9). Compared to dialysis, trips for other medical care were more likely to be cancelled for client and health reasons (ORs ranged 1.6-7.9). Higher levels of service increased cancelling for health reasons (OR=2.9 stretcher; OR=1.8 wheelchair). Finally, pre-scheduled or subscription trips were less likely to be cancelled and client factors differed for the cancellation of trips that were not regularly scheduled. The results of this initial study confirm that for this population additional transportation services are often not available and that more support for utilizing NEMT may be needed. Future research should evaluate persistent barriers, service delivery, and long-term outcomes.
Pedestrian and Bicycle University Education Joint Subcommittee Rebecca L. Sanders, SafeTREC, University of California, Berkeley, presiding
Monday, January 14, 2013 3:45PM - 5:30PM
Hilton, Northwest
Subcommittee meeting
Session 369 Preserving and Extending Mobility for Seniors, Part 2 (Part 1, Session 306)
Monday, January 14, 2013 3:45PM - 5:30PM
Marriott, Delaware A
Lectern Session
"Developing Safety Management Tools for State Departments of Transportation" 13-3936
Koohong Chung, California Department of Transportation; Offer Grembek, Jinwoo Lee, SafeTREC, University of California, Berkeley
Two different safety management tools had been recently developed for the California Department of Transportation (Caltrans): one is the Continuous Risk Profile (CRP) approach which is a network screening procedure, and the other is the California Safety Analyst (CASA) which is a web-based application designed to assist state safety engineers in conducting safety investigations and documenting their findings. This paper provides a qualitative description of these two tools and also summarizes feedback from over 100 Caltrans safety engineers who attended the demonstration of the web-based application. Findings from empirical analysis and the survey revealed that CRP can significantly reduce the false positive rate and that CASA can greatly improve the efficiency of traffic safety investigations. However, there still remain misunderstandings about the relationship among CRP, other methods explained in Highway Safety Manual, and different safety management tools. These misunderstandings impose challenges for the deployment of CRP and CASA in California and these challenges are also discussed in the paper.
Session 439 Transportation Safety Management and Alcohol Research
Monday, January 14, 2013 7:30PM - 9:30PM
Marriott, Salon 2
Poster Session | Practice Ready Papers
Tuesday, January 15, 2013
"Dissecting Perceived Traffic Risk as a Barrier to Adult Bicycling" 13-5264
Rebecca L. Sanders, SafeTREC, University of California, Berkeley
Nearly twenty years of federal policy has sought to increase bicycling trips to improve physical health, mitigate automobile pollution, and increase access–but research shows that people’s concerns regarding the risk of bicycling near traffic remain a significant barrier to widespread cycling. While an important finding, the research has not disaggregated “traffic risk” to expose its many aspects and how they may affect bicyclists with differing skill levels, experiences, and behaviors. This paper elaborates on results from a recent internet survey examining various aspects of traffic risk among 579 non-bicycling drivers, bicycling drivers, and non-driving bicyclists in the Bay Area. Analysis of variance tests revealed that bicyclists’ perceptions of danger differed according to riding frequency, with frequent cyclists more likely to fear more commonly reported crash types, while potential cyclists feared crashes that occur less frequently. In addition, an “exposure effect” seemed to appear such that those who bicycle occasionally reported the most fear of all bicyclists. Respondents also reported “near miss” experiences with motor vehicles. Nearly 70% of bicyclists in the sample have experienced a “near miss”, and 14% reported being hit. The data indicate that perceptions of traffic risk are related to near miss and crash experiences, although this differed according to bicycling frequency. These findings suggest that efforts targeting specific driver and bicyclist behaviors associated with these “near misses” could mitigate perceived traffic risk for bicyclists.
Session 494 Cycling Infrastructure and Safety
Tuesday, January 15, 2013 8:30AM - 10:15AM
Marriott, Salon 2
Poster Session | Practice Ready Papers
"Associations Between Road Network Structure and Pedestrian-Bicyclist Accidents" 13-4316
Yuanyuan Zhang, John M. Bigham, SafeTREC, University of California, Berkeley; Zhibin Li, Southeast University, China; David R. Ragland, SafeTREC, University of California, Berkeley; Xiaohong Chen, Tongji University, China
It is widely known that the road network layout can impact the non-motorized users’ traffic safety by changing the non-motorized traffic volume and road users’ behavior. Different road network patterns lead to different traffic safety levels for non-auto users and a single pattern can even have both the safe and unsafe features at the same time. By knowing what features can lead to safer traffic environment, existing road networks can be improved and new network patterns can be produced by combining all safe features from different patterns. Therefore, the associations between road network structure and pedestrian-bicyclist crashes are analyzed in this paper to determine how the structural features of a road network affect non-motorist safety. Three structural measures including average geodesic distance, network betweenness centrality, and overall clustering coefficient are calculated based on the road networks of 321 census tracts in Alameda County, California. Then the three measures together with other factors like traffic behavior, land use, transportation facility, and demographic features are employed separately in a spatial statistical model called geographically weighted regression. Conclusions are: if a network is more highly centered on major roads, there will be fewer non-motorist crashes; the network which has more average number of intersections between each pair of roads tends to have fewer accidents for pedestrians and bicyclists; and, the more a network is clustered into several sub-core networks, the lower the non-motorist crash count will be.
Session 494 Cycling Infrastructure and Safety
Tuesday, January 15, 2013 8:30AM - 10:15AM
Marriott, Salon 2
Poster Session | Practice Ready Papers
"Observational Study of Cell Phone and Texting Use Among California Drivers 2012 and Comparison with 2011 Data" 13-4877
Jill F. Cooper, David R. Ragland, SafeTREC, University of California, Berkeley; Katrin Ewald, Lisa Wasserman, Ewald & Wasserman Research Consultant, LLC; Christopher J. Murphy, California Office of Traffic Safety
This methodological report describes survey research and data collection methods employed for the second Observational Survey of Cell Phone and Texting Use among California Drivers study. This study was conducted by Ewald & Wasserman Research Consultants (E&W) on behalf of the California Office of Traffic Safety and the Safe Transportation Research and Education Center at University of California at Berkeley. The survey’s goal was to obtain a statewide statistically representative observational sample of California’s cell phone use behaviors, focusing on cell phone use. Vehicle drivers were observed at controlled intersections, such as traffic lights and stop signs, using a protocol similar to the National Occupancy Protection Use Study methodology published by the National Highway Transportation Safety Administration. The sample frame included a total of 5,664 vehicle observations from 129 sites. The total percentage of distracted driving by electronic devices (holding a phone to the ear, manipulating a hand-held electronic device while driving, or talking on a hand-held device) observed increased to 6.2% in 2012 from 4.2% in 2011. California’s baseline level of cell phone use and driving will be a critical metric over the years as traffic safety stakeholders mobilize to conduct high visibility enforcement campaigns, explore new policies, expand educational programs, and engineer countermeasures to increase safety on the roads.
Session 543 Driver Distraction, Driver State, and Vehicle Safety Systems
Tuesday, January 15, 2013 10:45AM - 12:30PM
Marriott, Salon 2
Poster Session
"Use of Passenger Facility Charges as a Funding Stream for Sustainable Transport Facilities at Airports" 13-5055
Phyllis Orrick, SafeTREC, University of California, Berkeley; Karen Trapenberg Frick, Univeristy of California Transportation Center, University of California, Berkeley
In this paper we use a case study approach to examine how airport operators have used Passenger Facility Charges to finance sustainable transport facilities, specifically multimodal transit and rail links, on their properties. Passenger Facility Charges (PFCs) are charges that airports may impose on boarding passengers to fund improvements on their properties. Under Federal Aviation Administration (FAA) requirements, PFC projects must enhance security, increase capacity, or reduce noise impacts. Importantly, unlike Airport Improvement Program (AIP) grants, the other significant FAA-administered improvement fund, PFCs can finance non-aeronautical projects (on the “land” side)—access roads, terminals and gates. This represents a potential major revenue stream for airport multimodal transit and rail connections. However, PFCS are limited to projects located on airport property and for the exclusive benefit of airport passengers, employees and visitors. We examine the types of projects that have been funded by these charges and obstacles to their use. Our findings suggest that there is growing airport operator interest in developing multimodal transit connections, as well as federal policy support. Motivations for this consideration include airport operators' increasing interest in improving their properties' sustainability. Through this research, we identify exemplar cases of PFC-funded intermodal projects and how FAA policy shaped them. We also identify areas for additional research: studies to develop deeper knowledge of effective airport intermodal strategies, more robust evaluation of economic impacts and effects on mode split and greater understanding of integrating airports with the surface transportation system, especially with recent federal and state policy efforts and discussions related to the development of high-speed rail.
Session 608 Current Issues in Aviation
Tuesday, January 15, 2013 2:00PM - 3:45PM
Shoreham, Blue Room Foyer Poster Session
"Classification of Bicycle Traffic Patterns in Five North American Cities" 13-3007 (practice-ready paper)
Luis Fernando Miranda-Moreno, Thomas Nosal, McGill University, Canada; Robert J. Schneider, University of Wisconsin-Milwaukee (formerly with SafeTREC); Frank Proulx, SafeTREC, University of California, Berkeley
This paper analyses bicycle ridership patterns using a unique database of automated bicycle counts from approximately 40 locations in five North American cities and along the Route Verte in Quebec. The cities involved in this study are Montreal, Ottawa, Portland, San Francisco, and Vancouver. Count data show that the bicycle volume patterns at each location can be classified as utilitarian, mixed utilitarian, recreational and mixed recreational. Study locations classified into each of these categories are found to have consistent hourly and weekly traffic patterns, despite important differences between these cities in terms of factors such as weather, size, and urban form. Expansion factors for each location type are presented by hour and day of the week. There were differences in seasonal patterns of bicycle activity between the study locations, so different monthly expansion factors are presented for each city. Finally, some traffic volume characteristics are presented for comparison purposes.
Session 640 Bicycle and Pedestrian Counting Data and Collection Methods
Tuesday, January 15, 2013 3:45PM - 5:30PM
Hilton, International East
Lectern Session | Practice Ready Papers
"Using Time-Based Metrics to Compare Crash Risk Across Modes and Locations" 13-0522
Sukran Ilgin Guler, Offer Grembek, David R. Ragland, SafeTREC, University of California, Berkeley
The objective of this work is to identify better metrics of exposure when comparing traffic crash risk across modes or across locations. We propose that total time travelled should be used for road user exposure to crash risk. The idea behind this is that travel time reflects the differences in speeds across different modes and hence should be used as the basic exposure metric from which crash risk based on other metrics, such as travel distance, can easily be derived. We also propose that when comparing crash risk of different modes across different locations the time based mode share should be used as an explanatory variable. By using mode share we are generalizing the safety in numbers concept which focuses on absolute numbers. This work presents a discussion on why these two metrics were chosen and how they are different from the commonly used metrics. Quantitative evidence for the choice of time based metrics is also presented using travel survey data to compare crash risk across modes and locations.
Session 658 Statistical Methods Research for Transportation
Tuesday, January 15, 2013 4:15PM - 6:00PM
Marriott, Salon
Poster Session
"Pedestrian Crash Risk on Boundary Roadways: University Campus Case Study" 13-5204
Robert J. Schneider, University of Wisconsin-Milwaukee (formerly with SafeTREC); Offer Grembek, Matthew Braughton, SafeTREC, University of California, Berkeley
Prominent pedestrian trip attractors, such as college campuses and major urban parks, are often surrounded by roadways with high volumes of motor vehicle traffic. While many pedestrians cross busy boundary roadways, relatively little is known about pedestrian crash risk along these types of facilities. This study quantifies pedestrian crash risk at roadway intersections on the boundary of the University of California, Berkeley campus during typical spring and fall semester weekdays. Manual pedestrian counts were extrapolated using data from three automated counter locations to represent pedestrian exposure. Pedestrian crash risk was highest at intersections along the boundary roadways with the lowest pedestrian volumes. In addition, pedestrian risk in the evening (6 p.m. to midnight) was estimated to be more than three times higher than in the daytime (10 a.m. to 4 p.m.). The crash risk estimation approach presented in this paper can be used to study pedestrian safety on the boundary of campuses and other major attractors so that agencies can identify and prioritize engineering, education, and enforcement treatments to reduce pedestrian injuries.
Session 669 Pedestrian Design, Safety, and Behavior
Tuesday, January 15, 2013 7:30PM - 9:30PM Marriott, Salon 2
Poster Session | Practice Ready Papers
Wednesday, January 16, 2013
"Empirical Analysis of Discretionary Lane Changes Using Probabilistic Models" 13-4629
Jinwoo Lee, SafeTREC, University of California, Berkeley; Hwasoo Yeo, Korea Advanced Institute of Science and Technology
This paper presents a stochastic approach for modeling discretionary lane changes with influential factors of velocity and spacing advantages. Lane changes are categorized into mandatory lane changes and discretionary lane changes. There are various factors which influence the decision-making involved in discretionary lane changes, including: for examples, relative velocity between target lane and original lane, and lead and lag gaps. This paper studies how velocity and spacing advantages affect the discrete lane change. This project uses Next Generation Simulation (NGSIM) data from traffic on U.S. Highway 101 and Interstate 80. Mandatory lane changes due to exiting/entering roadway ramps at the target site were filtered out using the proposed standards, in addition to some of the observed discretionary lane changes which were deemed false positives, but confident discretionary lane changes were considered. Driver behavior differs for mandatory and discretionary lane changes. This study proposes the use of an exponential probability function model with speed difference and lead gap difference between the target lane and the original lane, and proposes some restrictions of discretionary lane changes empirically. By transformed linear regression, these traffic variables have actual influences on the choice probability function of discretionary lane changes. Understanding the behavior of discretionary lane changes is important in safety, and may improve safety-related technologies.
Session 726 Traffic Flow Theory and Characteristics, Part 2 (Part 1, Session 497)
Wednesday, January 16, 2013 8:30AM - 10:15AM
Marriott, Salon 2
Poster Session | Practice Ready Papers