bluuebunny/crossref_metadata_2025 huggingface dataset:
Factors Affecting Common Vehicle-to-Vehicle Collision Types
Authors: Ulfarsson Gudmundur F. , Kim Sungyop , Lentz Eric T.
Published: May 2018

The number of older drivers (65+ years old) is increasing as a result of the baby boom generation reaching retirement age and an increase in driver's license holders among the elderly. The types of collisions incurred by older drivers are compared with those of drivers 30 to 60 years old in vehicle-to-vehicle collisions using the General Estimates System 2002–2003 sampling of reported motor vehicle collisions compiled by the NHTSA National Center for Statistics and Analysis. Multinomial logit vehicle-to-vehicle collision outcome models that account for driver, vehicle, roadway, environmental, and temporal characteristics were created for drivers age 65 and older and a comparison group of drivers 30 to 60 years old. The older drivers are significantly more prone to collisions related to vehicle turning and intersecting paths—particularly at signalized intersections—than are 30-to-60-year-old drivers. As a factor, age is elastic for same-direction and vehicle-turning crashes. Probability decreases with age for same-direction collision types but increases with age for vehicle-turning collision types, this indicates that difficulty with intersections increases for older drivers. Within the 30-to-60-year-old group, age was not significant. The results support findings of previous studies that older drivers tend to avoid driving in suboptimal conditions. The conclusions provide insight into roadway improvements that require priority for research and funding to make driving easier and safer for road users in general and older drivers in particular.
Design of Simulator Scenarios to Study Effectiveness of Electronic Stability Control Systems
Authors: Watson Ginger S. , Papelis Yiannis E. , Ahmad Omar
Published: May 2018

The mission of the National Advanced Driving Simulator is to conduct highway safety research that will reduce annual loss of life on U.S. roadways. The simulator is well suited in its ability to replicate vehicle dynamics—and associated motion and visual cues—realistically to conduct complex experiments. It is unique in its ability to study vehicle control and loss-of-control situations in a safe and controlled environment. These capabilities make it an appropriate device to study the effectiveness of electronic stability control (ESC) systems, in which proper handling during loss of vehicle control is critical to assess system efficacy. The focus of the study is on challenges associated with creating repeatable yet unexpected scenario events in which loss of control is imminent for most drivers. Scenario events designed for a large-scale experiment to study ESC systems are detailed, data derived from these scenarios are discussed, and findings of scenario effectiveness are presented. A discussion of what constitutes loss of control and how to measure its effect effectively is provided.
Assessing Driver Distraction from Cell Phone Use
Authors: Schattler Kerrie L. , Pellerito Joseph , McAvoy Deborah , Datta Tapan K.
Published: May 2018

The relative driving performance of 37 drivers was compared in a controlled laboratory environment to assess how cell phone use affects driver performance on urban arterials and local roads. The stimulus consisted of answering a call on a hand-held cell phone and engaging in a scripted conversation with study researchers. A driving simulator replicated various typical real-world driving environments and roadway situations. Subjects drove a control scenario (baseline condition) and a test scenario in which they were asked to answer a set of questions using a hand-held cell phone while driving. The subjects were required to navigate various conditions, such as respond to traffic signs and signals, negotiate vehicular traffic when turning, and yield to unexpected pedestrians and bicyclists. Driver performance was assessed for overall driver performance scores, speed profiles, vehicular lateral placement within travel lanes, and number of crashes that occurred during the simulator experiment. Changes in measures between control and test scenarios were subjected to a series of statistical tests. Analysis results indicated that when cell phones were used while driving, subject performance scores were significantly lower, average speeds significantly slower, and proportions of improper lateral placement observed significantly higher. In addition, twice as many crashes (also statistically significant) were observed when subjects used cell phones while driving as were observed under the control condition. In this controlled laboratory experiment, the distraction caused by answering a call and engaging in a conversation on a hand-held cell phone significantly degraded driving performance.
Highway Traffic Response to Dynamic Fog Warning and Speed Advisory Messages
Authors: MacCarley C. Arthur , Ackles Christopher , Watts Tabber
Published: May 2018

The response of traffic to messages displayed on a changeable message sign (CMS) warning of fog ahead and advising specific speeds at increasingly lower visibility levels is examined. Over a 2-year period, the speed, length, and time of detection were individually recorded for all vehicles at four sites: two before and two after a CMS. Mean speed, speed variance, and potential collision speed (PCS), a new metric, were calculated with a 45-s moving window and averaged over each constant message state. PCS is a predictor of impact speed in a potential chain collision that considers visibility as well as speed and separation between individual vehicles. When the CMS was activated, mean traffic speed decreased 1.1 mph on average over all fog events in comparison to mean speed in the absence of a message. However, average PCS increased differentially by 8 mph because of platoon compression and the sensitivity of this metric to increasingly worse visibility after the CMS during most activations. Speed standard deviation among proximate vehicles did not appear to be significantly affected—within 5 to 7 mph across all lanes in most cases. The warning messages evoked a measurable effect on driver behavior but well below design expectations. Drivers appeared to respond predominantly to their own perceptions and reduced speeds in fog, but not nearly enough to compensate for the reduced visibility. When the advised speed was 30 mph in dense fog, mean speeds averaged 61 mph.
Simple Way to Use Closed-Circuit Television Road Images for Poor-Visibility Information
Authors: Nagata Yasuhiro , Hagiwara Toru , Kaneda Yasuhiro , Araki Keiji , Murakami Keisuke
Published: May 2018

Road visibility information is important for driving safety, and the need for such information in winter is particularly great. Road administrators provide drivers with road images gathered using closed-circuit television (CCTV) cameras installed along national highways. However, when road condition information is given as an image, the provision media are limited. Japan's Hokkaido Regional Development Bureau has sought ways to quantify road image information. If it can be proved that the estimation of road visibility from the same image does not differ among people and if drivers’ assessments of visibility correlate with assessments given by a road image–based visibility scale (VS), then the VS can be used to quantify road visibility. VS is calculated from a weighted intensity of power spectrum developed by Hagiwara and colleagues. Subjective assessments of road images taken by CCTV cameras were surveyed. Assessments of daytime images also had little variation among subjects and correlated closely with the VS; assessments of nighttime images had little variation among subjects but did not correlate closely with the VS. To determine the best way to provide VS information, subjects’ understanding of information given was surveyed in response to three provision media (text, numerical rank, and symbol); the differences were small.
Enhancing Highway Geometric Design
Authors: Han Kai , Middleton Dan , Clayton Alan
Published: May 2018

Visualization based on virtual reality (VR) has gained increasingly wider recognition among transportation engineers and researchers because of advances in computer and VR technologies. The benefits of applying VR in transportation are well documented. However, many technical and financial issues hinder wide acceptance of this new technology in highway engineering design. Therefore, the concept of a custom-built, lightweight visualization system aimed at enhancing highway geometric design processes is developed. Capable of supporting the construction of a three-dimensional (3-D) road surface with accurate geometry and providing vehicle-based navigation with controlled driver perspectives, the visualization system is created by applying open-source VR modeling technology with proven key techniques. A systematic approach was taken to integrate data, create 3-D modules, and implement the visualization system as numerous case studies by using real-world data. The successful implementation proves the design concept, shows great potential for supporting the engineering design process, and opens new opportunities for further development.
Advanced Activity-Based Models in Context of Planning Decisions
Authors: Vovsha Peter , Bradley Mark
Published: May 2018

Travel demand modeling today is undergoing a transition from the conventional four-step models to a new generation of advanced activity-based models. The new generation of travel models is characterized by such distinctive features as the use of tours instead of trips as the base unit of travel, the generation of travel in the framework of daily activity agendas of individuals, and the use of fully disaggregate microsimulation techniques instead of the aggregate zonal calculations. Although the theoretical advantages of activity-based models—in particular, behavioral realism and consistency across all travel dimensions—are well known, the practical advantages in the context of planning decisions have rarely been discussed and documented. Experiences to date are summarized for application of activity-based models for various planning purposes in metropolitan regions of New York City; Columbus, Ohio; Atlanta, Georgia; San Francisco, California; and Montreal, Canada. The focus is on the practical planning questions and policies that were analyzed with these models and their relative strengths and advanced features compared with the four-step models. The planning questions and policies include congestion pricing schemes, high-occupancy-vehicle facilities, parking policy, testing impacts of demographic scenarios, and so on. It is shown that activity-based models are capable of treating these planning and policy issues at the level at which four-step models become inadequate.
Summary of Recommendations from Travel Model Improvement Program's Peer Review Program
Authors: Culp Michael , Lee Esther , Steffes Ann M.
Published: May 2018

The U.S. Department of Transportation, through FHWA, sponsors the Travel Model Improvement Program (TMIP) to help planning agencies improve their travel analysis techniques. As an integral part of TMIP, the Peer Review Program provides state and local planning agencies the ability to solicit input from experts in the field of travel demand modeling. The purpose of the Peer Review Program is allow experts in the field of modeling offer guidance to ensure that technical products, procedures, and processes are being developed to meet an agency's specific needs, as well as state, federal, and local planning requirements. Between June 2003 and December 2004, the TMIP Peer Review Program sponsored 12 peer review panels that occurred across a broad spectrum of metropolitan planning organizations (MPOs) and state departments of transportation (DOTs) throughout the United States. The peer review panel members included representatives from MPOs, state DOTs, private consulting firms, education institutions, and environmental interest groups. While the results of each peer review were documented individually and posted to the TMIP website, TMIP sponsored an additional study on the common issues and trends that arose within the peer reviews. The results of the peer reviews have been compiled and analyzed in a TMIP Peer Review Program synthesis report that will be a useful tool for planning practitioners interested in the experiences and lessons learned from peer agencies across the nation. Common issues and trends documented in the synthesis report and in subsequent TMIP peer reviews are summarized.
Geography of Public Participation
Authors: Prevost Daniel L.
Published: May 2018

How effective are public involvement programs in reaching a representative and sufficient sampling of public input for a planning study? While evaluations of public involvement programs are traditionally qualitative, this paper shows how geographic information systems (GIS) can provide an appropriate and productive means of quantitatively evaluating the effectiveness of an agency's outreach program. This study used both mailing list and comment data from the Dulles Corridor Rapid Transit Project Environmental Impact Statement of the Virginia Department of Rail and Public Transportation to evaluate the agency's outreach program. The data were analyzed to determine the project's effectiveness in informing and receiving feedback from potential stakeholders. The analysis showed that 50% of the mailing list members lived within 1/2 mi of the proposed project. “Inclusion rates” were calculated, with household participation rates in census block groups near the project ranging from 0 to 82%. The Tysons Corner segment of the project, where the proposed rail line would be closest to residences, on average had the highest inclusion rates, with 16.5% of households within 1/2 mi of the proposed stations participating. Of the six block groups meeting the project's environmental justice thresholds, half had an inclusion rate below 5%. Analysis of commenters showed that those closest to the project were most likely to comment on the study and to express opposition to the project in their comments. This study reinforces many traditional stereotypes in public participation, but, more important, it demonstrates a method by which deficiencies in outreach efforts can be identified and measures taken to improve participation. By using the GIS-generated maps, agencies can readily identify geographic areas that may be affected by the project, yet have low participation rates, and use this information to develop additional outreach tools to target these populations.
Views of the Street
Authors: McAndrews Carolyn , Flórez Josefina , Deakin Elizabeth
Published: May 2018

Urban transportation planners need community involvement to design the urban transportation system for its users and for those who experience its spillovers and externalities, positive and negative. The people in the urban transportation system include travelers, residents of nearby neighborhoods, transit service providers, and others. These groups often overlap. This paper discusses methods and findings from an effort to involve residents in the planning for the redesign and revitalization of San Pablo Avenue, an urban arterial running along the eastern edge of the San Francisco Bay, California. The viewpoints of residents of neighborhoods of Oakland, Emeryville, Berkeley, Albany, Richmond, and El Cerrito, California, the six cities along the southern portion of the avenue, were gathered through resident surveys and focus groups. These residents experience the avenue as travelers and also as its neighbors, whose everyday lives are influenced by activities on the street. Resident surveys and focus groups show that even on a major arterial serving multiple jurisdictions, local residents account for a major share of shopping and personal business along the arterial, and local trips are a major portion of the pedestrian traffic, transit ridership, and auto use in the corridor. Further, residents have intimate knowledge of the way the street functions and malfunctions and can offer useful suggestions for street redesign, operational improvements, land use changes, and related social programs. The paper shows that context-sensitive design needs to respond not only to the physical environment but also to social and economic conditions, including neighborhood concerns and aspirations.
Developing a Simple System for Conflict Management of Public Involvement
Authors: Barnes Gary , Erickson Stephanie
Published: May 2018

Although commercially taught systems are effective for managing conflict that arises during public involvement in transportation projects, these systems can be costly and complex. They appear more appropriate for those who can use them frequently. The work described here, by contrast, was focused on finding simple methods for managing less challenging projects and was aimed toward those who may use public involvement only occasionally. The conflict management framework is derived from a distillation of expert opinion, based on discussions of specific projects by Minnesota transportation experts on public involvement. They were interviewed with a standard set of questions about the project, the public involvement process, the reasons for conflict, how the conflict was managed, what worked, and what did not. The interviews encompassed a variety of project types and settings. The framework has two components. The first is a simple organizational scheme for categorizing conflict to assist in determining the appropriate management strategy. The second is the management strategies themselves. An overview of the key elements of these components is given.
Direct Demand Forecasting Model for Small Urban Communities Using Multiple Linear Regression
Authors: Anderson Michael D. , Sharfi Khalid , Gholston Sampson E.
Published: May 2018

Forecasting traffic volumes to support infrastructure decisions is the heart of the travel demand modeling process. The most commonly used methodology for obtaining these forecasted traffic volumes is the four-step process that considers generation, distribution, mode choice, and route assignment of trips. Each step of the process is performed independently, almost always through the use of computer software, to achieve the final traffic volumes. This paper examines the possibility of forecasting traffic volumes by using a multiple linear regression model to perform what is termed direct demand forecasting. The direct demand forecasting model generates traffic volumes for roadways through the development of a functional relationship between roadway characteristics and socioeconomic influences. A direct demand travel forecasting model has been developed and applied, with a small urban area as a case study community. Results are consistent with those obtained from the traditional four-step methodology.
Financial Benefits of Early Acquisition of Transportation Right-of-Way
Authors: Barnes Gary , Watters Sarah
Published: May 2018

Right-of-way acquisition is a substantial element of the cost of many highway construction and expansion projects. Given land price appreciation on the one hand and the opportunity cost of owning land on the other, a great deal of money can be at stake in the question of whether right-of-way should be purchased well in advance of when construction is expected to take place. This paper develops a theoretical framework for thinking about this issue and describes some results from an analysis at a fairly aggregate geographic level. The general result is that early acquisition is not a good investment in the most general sense, given the average rate of land price increase and the cost of money as well as other costs associated with early acquisition. The one clear exception is land that is in imminent danger of development. A major limitation of this work is that it viewed land prices only in the aggregate and did not specifically examine the immediate vicinity of the right-of-way. The research did find some support for the notion that certain types of land in specific locations can appreciate in price much faster than the average. It is not clear, however, that it is possible to predict these situations with sufficient accuracy to take advantage of the potential cost savings.
Documenting America's National Park Roads and Parkways
Authors: Davis Timothy
Published: May 2018

America's national park roads and parkways are outstanding design achievements exemplifying the harmonious integration of highway engineering and landscape architecture. By designing roadways to showcase scenery with minimal impact on their surroundings, the National Park Service created an internationally renowned road system that provides access to America's most treasured landscapes while standing as a remarkable social, artistic, and technological achievement in its own right. From 1988 to 2002, the Historic American Engineering Record conducted a documentation project that produced more than 4,000 photographs, 476 measured and interpretive drawings, and more than 10,000 pages of written history. These reports document the roads’ physical characteristics and articulate their social, technological, and aesthetic influences. Not every park could be surveyed, but the most prominent roads were documented in detail. Several non–Park Service roads were also documented, including the Historic Columbia River Highway and the Merritt, Bronx River, and Taconic State Parkways. This documentation has multifold purposes: it provides a permanent record of America's design heritage; it serves as a guide for management, planning, preservation, and public outreach activities; it provides a rich source of information for contemporary context-sensitive design efforts; and the research methodology provides a model for future efforts to document large-scale engineering works. The documentation has appeared in numerous exhibitions and publications, including a 400-page volume titled America's National Park Roads and Parkways: Drawings from the Historic American Engineering Record (Johns Hopkins University Press, 2004).
Lifestyles, Residential Location Decisions, and Pedestrian and Transit Activity
Authors: Krizek Kevin J.
Published: May 2018

The idea of using land use patterns to influence people's behavior is popular in urban planning circles these days. Activity-based travel modeling has begun to make significant progress toward a more behavioral framework for simulating household travel behavior and understanding, in particular, pedestrian activity. A significant challenge remains in the need to address the interaction of pedestrian use with longer-term household choices of neighborhood choice, other activities, and overall travel. The choices often depend on one another and jointly define the lifestyle of an individual. This paper refines a framework to analyze household choices relating to three dimensions of lifestyle: travel patterns (including pedestrian activity), activity participation, and neighborhood characteristics. Cluster analysis on data from the Twin Cities metropolitan region in Minnesota uncovers seven classifications of lifestyle. These clusters demonstrate empirically how decisions about residential location reinforce and affect daily decisions related to travel patterns, pedestrian and transit use, and activity participation. The final section comments on the applicability of these lifestyle clusters for land use–transportation planning.
Another Look at Pedestrian Walking Speed
Authors: Fitzpatrick Kay , Brewer Marcus A. , Turner Shawn
Published: May 2018

Pedestrians have a wide range of needs and abilities. FHWA's Manual on Uniform Traffic Control Devices for Streets and Highways includes a walking speed of 4.0 ft/s (1.2 m/s) for calculating pedestrian clearance intervals for traffic signals. It also includes a comment that where pedestrians who walk slower than normal, or pedestrians who use wheelchairs, routinely use the crosswalk, a walking speed of less than 4.0 ft/s should be considered in determining the pedestrian clearance times. A 2005 TCRP-NCHRP study found a 15th percentile walking speed for young pedestrians of 3.77 ft/s (1.15 m/s) and a 15th percentile walking speed for older pedestrians of 3.03 ft/s (0.92 m/s). The study also determined that there is a statistical difference in walking speeds between older (older than 60 years) and younger (60 years and younger) pedestrians. Using population projections and the 15th percentile walking speeds for each population group more than 15 years old, the proportionally weighted 15th percentile walking speed for 2045 is 3.56 ft/s (1.09 m/s). Comparing the findings from the TCRP-NCHRP study with previous work results in the following recommendations: 3.5-ft/s (1.07-m/s) walking speed for timing of a traffic signal; if older pedestrians are a concern, then a 3.0-ft/s (0.9-m/s) walking speed should be used.
Accessible Pedestrian Signals
Authors: Bentzen Billie Louise , Scott Alan C. , Barlow Janet M.
Published: May 2018

The U.S. Access Board's Draft Guidelines for Accessible Public Rights-of-Way recommends the use of push-button-integrated accessible pedestrian signals (APSs). This research compared the effect of specific features of push-button-integrated APSs on the ability of blind pedestrians to locate and correctly use push buttons and to cross accurately during the pedestrian phase. A rapid-tick walk signal promoted the fastest onset of crossing compared with speech messages and bird calls and is therefore the preferred signal. However, speech walk indications are needed where two APSs are mounted on the same pole. Although variations in the standard features made little difference to users who were thoroughly familiar with devices, empirical evidence from participants with less knowledge of the devices as well as subjective data lead to the recommendation that APS devices include a push-button locator tone, a rounded push button with an activation tone or message, a tactile arrow incorporated into the push button, responsiveness to ambient sound, and a push-button information message and beaconing in response to an extended button press.
Microscopic Parameter Identification of Pedestrian Models and Implications for Pedestrian Flow Modeling
Authors: Hoogendoorn Serge P. , Daamen Winnie
Published: May 2018

This paper focuses on the calibration of microscopic pedestrian models using pedestrian trajectory data. A generic approach that enables parameter identification for microscopic models in general and for walker models in particular is proposed. The application results provide insight into the behavior of individual pedestrians and interpedestrian differences as well as the resulting pedestrian flow characteristics. Different models of increasing complexity were compared to investigate which model amendments are significant from a statistical point of view. Besides anisotropy, finite reaction times play an important role in correctly describing microscopic walking behavior. The implications of these findings in the microscopic description of pedestrian flows are considered by studying the predicted flow operations at a narrow bottleneck. The finite reaction times have a significant effect on the pedestrian flow operations and should be included in pedestrian models to ensure realistic predictions.
Analysis of Driver and Pedestrian Comprehension of Requirements for Permissive Left-Turn Applications
Authors: Knodler Michael A. , Noyce David A. , Kacir Kent C. , Brehmer Christopher L.
Published: May 2018

Operations engineers commonly program traffic signal controllers to serve the pedestrian movement at the same time as the parallel vehicular-through movement. This requires drivers completing a permissive left-turn movement to yield to opposing vehicles and pedestrians before selecting an appropriate gap. To minimize the potential safety problem, it is critical that drivers and pedestrians understand the permissive left-turn signal indications. The recently completed NCHRP Report 493 identified that a flashing yellow arrow (FYA) permissive indication provided a preferred alternative to the existing circular green permissive indication and recommended that the FYA permissive indication be included in the Manual on Uniform Traffic Control Devices. This paper presents research findings of a follow-up study that targeted the FYA impact on pedestrians, including driver comprehension of the need to yield to pedestrians and pedestrians’ recognition of appropriate crossing opportunities. Driver and pedestrian comprehension of the FYA indication was evaluated with a series of dynamic driving simulator evaluations and computer-based static evaluations. In total, 139 drivers and 100 pedestrians were evaluated in 5,930 experimental scenarios. The FYA permissive indication can be safely and effectively used at intersections with pedestrian activities. Given the high level of comprehension to yield requirements, the FYA is a recommended indication at T-intersections where pedestrian crossings are prevalent. Fewer than half the pedestrians understood correct crossing procedures when pedestrian signal heads were not present, and pedestrian comprehension of the walking requirements under a flashing “don't walk” were quite low in all scenarios evaluated.
Pedestrian Level-of-Service Model for Urban Arterial Facilities with Sidewalks
Authors: Petritsch Theodore A. , Landis Bruce W. , McLeod Peyton S. , Huang Herman F. , Challa Srikalyan , Skaggs Cherie L. , Guttenplan Martin , Vattikuti Venkat
Published: May 2018

This paper documents a study sponsored by the Florida Department of Transportation to develop a level-of-service (LOS) model that represents pedestrians’ perceptions of how well urban arterials with sidewalks (a combination of roadway segments and intersections) meet their needs. The model incorporates traffic volumes on the adjacent roadway and exposure (i.e., crossing widths) at conflict points with intersections and driveways. Data were obtained from Walk for Science, an innovative field data collection event, and consist of participants’ perceptions of how well urban arterials with sidewalks meet their needs as pedestrians. The pedestrian LOS model for roadway facilities described here is based on Pearson correlation analyses and stepwise regression modeling of about 500 combined real-time perceptions (observations) from pedestrians walking a course along streets in a typical U.S. metropolitan urban area. Study participants represented a cross section of age, gender, walking experience, and residency. Although further hypothesis testing may be conducted in a future study, the resulting general model for the pedestrian LOS of urban arterials with sidewalks has a high correlation coefficient ( R2 = .70) with the average observations and is transferable to a significant number of metropolitan areas in the United States. The study reveals that traffic volumes on the adjacent roadway and the density of conflict points along the facility are the primary factors in the LOS model for pedestrians traveling along urban arterials with sidewalks.
Causative Factors and Trends in Florida Pedestrian Crashes
Authors: Spainhour Lisa K. , Wootton Isaac A. , Sobanjo John O. , Brady Patrick A.
Published: May 2018

A case study review of 353 fatal pedestrian crashes that occurred in Florida, primarily in 2000, identified contributing causes and trends of predominant pedestrian crash types. Researchers reviewed state records, traffic crash reports, traffic homicide investigative report narratives, diagrams, and photographs and incorporated select accident reconstructions and site visits. Results indicate that the most significant causes of pedestrian crashes are pedestrian behavior, alcohol use by pedestrians and drivers, poor pedestrian visibility at night coupled with violation of driver expectation, and lack of compliance with state laws. Some form of pedestrian behavior was the primary contributing factor in more than three-fourths of the pedestrian crashes reviewed. Alcohol use by the pedestrian or the driver was determined as the primary factor in 45% of the cases. Where alcohol use was determinable, 69% of pedestrians crossing not in crosswalks were under the influence. Dark conditions or insufficient lighting was a contributing factor in 60% of the cases. In nearly half the noncrosswalk crossing cases, pedestrians were attempting to cross the road within 600 ft of a traffic signal, many times violating driver expectation and right-of-way. Other factors were detected within a specific type of pedestrian crash; for instance, in half of the 15% of cases that occurred on limited access facilities, a significant contributing factor was the former occupant having exited a disabled vehicle. In 57% of the cases in which a pedestrian was walking along the roadway, there was not a sidewalk for the pedestrian to use. Further research into countermeasures is recommended.
Walking in Waikiki, Hawaii
Authors: Kim Karl , Hallonquist Lauren , Settachai Napat , Yamashita Eric
Published: May 2018

This study examines pedestrian conditions in Waikiki, the most urbanized area in Honolulu, Hawaii. Focusing on one side of approximately a four-block stretch of Kalakaua Avenue, a series of 15-min pedestrian counts was conducted to establish overall sidewalk volumes and flows. Detailed maps were produced to characterize the physical environment and to identify potential factors associated with measurement of the pedestrian environment. Next, the pedestrian level of service (LOS) was estimated. A variety of factors affect the pedestrian environment. In addition to the width of the sidewalk, there are also movable and immovable objects, street furniture, plantings, and other activities that affect access and use of sidewalks. The intent of this study was to understand and measure better the impacts of sidewalk activities on LOS. To test and refine the approach, the impacts of street performers who occupied the sidewalks in the area were analyzed in terms of the effects on pedestrian flow and LOS. Street performers create the following kinds of impacts to the pedestrian environment: ( a) increased delay, ( b) direction changes and longer travel paths for pedestrians, ( c) increased traffic conflicts as pedestrians step into moving motorized traffic to avoid congestion, ( d) disruption of pedestrian platoons or preferred side of sidewalk for travel (generally, most pedestrians prefer to walk on the right side of the sidewalk), and ( e) increased confusion associated with crowding and forced changes in direction. Policy considerations as well as directions for research are discussed in a concluding section.
Variation of Walking Speeds on a Unidirectional Walkway and on a Bidirectional Stairway
Authors: Lee Jodie Y. S. , Lam William H. K.
Published: May 2018

The variation of walking speeds for passengers passing through a facility within a congested underground station is known to be an important factor influencing pedestrian route choices. This paper describes a study of walking speed variation under unidirectional and bidirectional pedestrian flow conditions in Hong Kong, China, mass transit railway stations. The studied facilities selected for data collection and analysis include a unidirectional walkway and a bidirectional stairway. The variation in walking speed is due to increased passenger demand in the station when trains arrive. A study of the distribution of walking speed variation and relationships between average walking speed and variations of that speed was conducted based on data collected from an observation survey. For uncongested sections, when the mean walking speed decreased, the walking speed variation also decreased under both unidirectional and bidirectional pedestrian flow conditions. In addition, the walking speed variation was smallest when pedestrian flow approached capacity. However, in congested sections, when the mean walking speed decreased, the walking speed variation increased under both unidirectional and bidirectional pedestrian flow conditions. All walking time data were empirically proved to present a normal distribution. This paper presents newly developed walking speed variation models for three selected pedestrian facilities. These models can be further considered in connection with pedestrian simulation models to assess alternative improvement schemes at urban railway stations.
Exploration of Pedestrian Gap-Acceptance Behavior at Selected Locations
Authors: Brewer Marcus A. , Fitzpatrick Kay , Whitacre Jeffrey A. , Lord Dominique
Published: May 2018

This paper describes the efforts to evaluate pedestrian gap acceptance as part of a recent TCRP-NCHRP project. Pedestrian crossing data were collected at 42 study sites in seven states. From those sites, 45 pedestrian approaches had at least one crossing event where a pedestrian rejected at least one gap, and 11 of those approaches had at least 20 such crossing events. Focusing on the 11 approaches, researchers evaluated the gap-acceptance behavior of crossing pedestrians with a two-part analysis: behavioral analysis and statistical analysis. Behavioral analysis revealed that pedestrians did not always wait to cross the street when all lanes were completely clear; instead, they anticipated that the lanes would clear as they crossed and used a “rolling gap” to cross the street. Statistical analysis revealed that the 11 approaches had 85th percentile accepted gaps between 5.3 and 9.4 s, with a trend of increasing gap length as crossing distance increased. All the observed 85th percentile accepted gaps were less than the critical gap as defined in the Manual on Uniform Traffic Control Devices for a walking speed of 3.5 ft/s (1.1 m/s) at their respective sites; this indicates that if 3.5 ft/s (1.1 m/s) were used as the design criterion, it would be sufficient to serve at least 85% of the observed pedestrians at the study sites.
Crossing Locations, Light Conditions, and Pedestrian Injury Severity
Authors: Siddiqui Naved A. , Chu Xuehao , Guttenplan Martin
Published: May 2018

This paper assesses the role of crossing locations and light conditions in the severity of pedestrian injuries through a multivariate regression analysis to control for many other factors that also may influence pedestrian injury severity. Crossing locations include midblock and intersections, and light conditions include daylight, dark with street lighting, and dark without street lighting. The paper formulates a theoretical framework on the determinants of pedestrian injury severity and specifies an empirical model accordingly. The paper applies the ordered probit model to the KABCO severity scale of pedestrian injuries that occurred while attempting street crossing in the years 1986–2003 in Florida. In terms of crossing locations, the probability of a pedestrian dying when struck by a vehicle is higher at midblock locations than at intersections for any light condition. The odds of sustaining a fatal injury are 49% lower at intersections than at midblock locations under daylight conditions, 24% lower under dark-with-street-lighting conditions, and 5% lower under dark-without-street-lighting conditions. Relative to dark conditions without street lighting, daylight reduces the odds of a fatal injury by 75% at midblock locations and by 83% at intersections, whereas street lighting reduces the odds by 42% at midblock locations and by 54% at intersections.
Safety in Numbers
Authors: Geyer Judy , Raford Noah , Pham Trinh , Ragland David R.
Published: May 2018

This paper adds material to the ongoing body of literature exploring the effect of pedestrian volume on safety for pedestrians. Observed and existing data for 247 intersections in Oakland, California, were used to model the effect of pedestrian volume on the number and rate (number of collisions per pedestrians) of vehicle–pedestrian collisions at or near these intersections. The study used a data set containing pedestrian collisions, average annual pedestrian volume, average annual vehicle volume, and other intersection characteristics. Estimates of the model parameters show that the number of pedestrian collisions increases more slowly than the number of pedestrians; that is, the collision rate decreases as the number of pedestrians increases, consistent with previous studies by Leden and Jacobsen. Specifically, a doubling of the number of pedestrians (increase of 100%) is associated with only a 52% increase in the number of vehicle–pedestrian collisions, with the corresponding rate decreasing by about 24%. If further research shows this association to be causal, and not due to variation in intersection characteristics or selection factors involving pedestrian choice, the implications for policy and planning involving pedestrians are substantial.
Observational Analysis of Pedestrian, Bicyclist, and Motorist Behaviors at Roundabouts in the United States
Authors: Harkey David L. , Carter Daniel L.
Published: May 2018

Roundabouts continue to gain popularity in the United States as an intersection treatment for improving operational efficiency and motor vehicle safety. A number of studies conducted in the United States and other countries have shown the benefits of roundabouts for these purposes. However, there is still concern that roundabouts may not provide safety or operational benefits for pedestrians and bicyclists. Crash-based studies of pedestrian and bicyclist safety in the United States have fallen short because of the relatively small number of roundabouts installed to date, which results in sample size issues due to the low number of motor vehicle collisions involving pedestrians and bicyclists. This study was undertaken as part of an NCHRP project. This paper focused on analyzing the interactions between motorists and pedestrians or bicyclists at roundabouts. This research did not find any substantial safety problems for nonmotorists at roundabouts based on conflicts or collisions. At the same time, the findings from behavioral observation have highlighted some aspects of roundabout design that require additional care to ensure safe access for pedestrians and bicyclists. Emphasis needs to be placed on designing exit legs to ensure proper sight lines and motor vehicle speeds. The junction of the circulatory lane and exit lane was observed to be the location of greatest risk for bicyclists. Multilane roundabouts may require additional traffic control measures to ensure safe access for pedestrians.
Preservation of Historic Transportation Facilities
Authors: Lichtenstein Abba
Published: May 2018

About 10,000 highway bridges in the United States qualify for inclusion on the National Register of Historic Places, but the path to preservation is full of obstacles, both political and financial. This lecture deals with highway bridges and aqueducts and includes photographs of the various projects discussed. It is hoped that no deserving historic facility will disappear without a public hearing and discussion.
Integrating Information Technology in Efficient Transportation Decision Making
Authors: Bejleri Ilir , Roaza Ruth , McGilvray Peter , Thomas Alexis
Published: May 2018

Florida's Efficient Transportation Decision Making (ETDM) process, developed in response to the U.S. Congress Environmental Streamlining initiative, is a new way of accomplishing transportation planning to achieve early agency participation, efficient environmental review, and meaningful dispute resolution. ETDM is accomplished through the environmental screening tool (EST), a technological solution to integrate resource and project information from multiple sources, to provide quick and standardized analysis of environmental and sociocultural effects of proposed projects, and to support effective communication of results to all stakeholders, including the public. EST was developed through a methodology of rapid software prototyping, frequent user feedback, and flexible architecture designed to adapt to the ETDM evolution process. This development resulted in an Internet-accessible interactive database and mapping application that integrates a georelational database of ETDM projects, more than 200 environmental resource geographical information system data layers, automated and standardized GIS-based environmental screening analysis, and numerous data entry, review, and reporting tools. For more than 2 years of operation with a user community from seven Florida Department of Transportation districts, 26 metropolitan planning organizations, 24 resource agencies, and the public, EST has proved successful in supporting the ETDM process. More than 600 projects are in the EST database, and more than 160 of them have completed the environmental review process. Examples of many benefits of the EST in the ETDM process include early identification of avoidance or minimization options, improved interagency communication and coordination, and the use of EST for applications beyond the ETDM purview.
Surface Retexturing to Reduce Tire–Road Noise for Existing Concrete Pavements
Authors: Herman Lloyd , Withers Jared , Pinckney Elvin
Published: May 2018

A portion of I-76 near Akron, Ohio, was reconstructed by the Ohio Department of Transportation with concrete pavement to replace the previous asphalt surface. During reconstruction, the concrete surface was textured with random transverse grooves. After construction, residents living in the project area as far as 800 m (2,600 ft) from the roadway perceived an undesirable increase in noise level, which they attributed to the new concrete pavement in the reconstruction project. Therefore, another project was initiated to retexture the pavement surface by diamond grinding. The transverse grooves were replaced with longitudinal grooves. Traffic noise measurements were made before and after grinding at five sites in the project area, at distances of 7.5 m (24.6 ft) and 15 m (49.2 ft) from the center of the near travel lane. The average reduction in the A-frequency–weighted broadband noise levels at 7.5 m (24.6 ft) was 3.5 dB, and the average reduction at 15m (49.2 ft) was 3.1 dB. Spectrum analysis showed that the greatest reduction in noise occurred at frequencies above 1 kHz and that the retexturing had little to no effect on frequencies less than 200 Hz.
Environmental Justice Assessment in Racially Diverse Areas
Authors: Li Honglong , Young Steve , Low Shevaun , Lum Gordon
Published: May 2018

This paper explores analytical techniques to identify the environmental justice (EJ) population in a racially diverse area and to evaluate the benefits and burdens of transportation projects upon EJ and non-EJ populations. A statistical technique was developed to identify the block groups where minority and low-income populations were disproportionately concentrated, with variation in the size of the block groups taken into account. Four performance measures that represent the transportation benefits of and burdens on the identified EJ and non-EJ areas were determined to evaluate accessibility, mobility, safety, and equity. Specific questions and indexes for each performance measure were developed to define disproportionate impacts. To establish transportation projects’ connection with local communities, those projects were categorized and selected on the basis of their type in addition to their geographical location. The method developed for Oahu, Hawaii, is transferable to states, cities, and metropolitan areas throughout the United States.