bluuebunny/crossref_metadata_2025 huggingface dataset:
Application and Integration of Lattice Data Analysis, Network K-Functions, and Geographic Information System Software to Study Ice-Related Crashes
Authors: Khan Ghazan , Santiago-Chaparro Kelvin R. , Qin Xiao , Noyce David A.
Published: January 2010

Advances in geographic information system (GIS) software and exploratory spatial data analysis (ESDA) techniques give transportation safety engineers tools to observe and analyze safety-related data from a new perspective. This research takes the use of GIS software and ESDA techniques one step further by incorporating advanced statistical techniques for a more thorough and complex analysis of safety data. This is achieved by implementing a network-constrained cross K-function to analyze the relationship between bridges and the occurrences of ice-related crashes within a county. The counties in Wisconsin included in the analysis were selected through the use of the local Moran's I statistic; this statistic allows for the selection of counties within the same geographical area, which have similar parameters (in this case, ice-related crash rates). The objective of this research is to explore the relationship between ice-related crashes and bridges in counties that display similar ice-related crash rates, to compare and analyze winter maintenance techniques. The results identify clustering of ice-related crashes around bridges in four counties with similar ice-related crash rates in southeast Wisconsin. Similarly, two of four counties show clustering of ice-related crashes around bridges in northwest Wisconsin. These results make a strong case to suggest that counties in these regions should focus additional winter maintenance efforts at bridge locations. In addition, this research shows how the use of advanced spatial statistical techniques, particularly network-based statistics applied within a GIS environment, can be used as a unique and innovative approach toward safety data analysis.
Application of Bayesian Statistics to Identify Highway Sections with Atypically High Rates of Median-Crossing Crashes
Authors: Davis Gary A. , Xiong Hui , Tao HunWen
Published: January 2010

This paper describes a Bayesian statistical technique for using crash records to estimate the frequency and rate of median-crossing crashes (MCCs) on each set of highway sections, in cases where MCCs are not explicitly identified in computerized crash records. This technique requires an analyst to review only a subset of hardcopy accident reports to produce a training sample, which is then used to identify computerized data associated (possibly imperfectly) with whether a crash was an MCC. This association can then be exploited to use larger sets of computerized records to increase statistical power over that provided by the training sample alone. This technique is applied to data from Minnesota's freeways and rural expressways. Estimates that allow highway sections to be ranked according to the estimated frequency or density of MCCs, or to the estimated MCC rate, are computed, and then the estimated frequency rankings are reported.
Bayesian Multivariate Poisson Lognormal Models for Crash Severity Modeling and Site Ranking
Authors: Aguero-Valverde Jonathan , Jovanis Paul P.
Published: January 2010

Traditionally, highway safety analyses have used univariate Poisson or negative binomial distributions to model crash counts for different levels of crash severity. Because unobservables or omitted variables are shared across severity levels, however, crash counts are multivariate in nature. This research uses full Bayes multivariate Poisson lognormal models to estimate the expected crash frequency for different levels of crash severity and then compares those estimates to independent or univariate Poisson lognormal estimates. The multivariate Poisson log-normal model fits better than the univariate model and improves the precision in crash-frequency estimates. The covariances and correlations among crash severities are high (correlations range from 0.47 to 0.97), with the highest values found between contiguous severity levels. Considering this correlation between severity levels improves the precision of the expected number of crashes. The multivariate estimates are used with cost data from the Pennsylvania Department of Transportation to develop the expected crash cost (and excess expected cost) per segment, which is then used to rank sites for safety improvements. The multivariate-based top-ranked segments are found to have consistently higher costs and excess costs than the univariate estimates, which is due to higher multivariate estimates of fatalities and major injuries (due to the random effects parameter). These higher estimated frequencies, in turn, produce different rankings for the multivariate and independent models. The finding of a high correlation between contiguous severity levels is consistent with some of the literature, but additional tests of multivariate models are recommended. The improved precision has important implications for the identification of sites with promise (SWiPs), because one formulation includes the standard deviation of crash frequencies for similar sites as part of the assessment of SWiPs.
Spatial Autocorrelation and Bayesian Spatial Statistical Method for Analyzing Intersections Prone to Injury Crashes
Authors: Mitra Sudeshna
Published: January 2010

Identification of hazardous road locations (i.e., crash hot spots or black spots) is a standard practice in departments of transportation (DOTs) throughout the United States. Often, DOTs use relatively straightforward methods to detect high crash sites; these methods, however, may not be accurate. The objectives of this study are to develop two different methodologies: ( a) a geographic information system (GIS)-based method to detect crash hot spots and ( b) a spatial regression method with structured and unstructured random effects in continuous space to investigate the intersection-level factors that influence the concentration of fatal injury crashes. Using injury and property damage only (PDO) crash data from Tucson, Arizona, this study shows that spatial dependence plays a strong role during the analyses of road-traffic crashes. These spatial dependencies, accounted through spatial autocorrelation, help to detect statistically significant clusters of crashes involving fatalities or severe or minor injuries, in a GIS framework. This study also develops statistical models of severe- and minor-injury crashes, using classical negative binomial (NB) and Bayesian spatial statistical methods incorporating spatially structured and unstructured random effects. The coefficient estimates from a Bayesian framework are similar to those from NB estimation, but with better precision. The model that includes spatial correlations also indicates the potential to reduce the bias associated with model mis-specification by changing the estimate of the annual average daily traffic coefficients. This study's results also indicate that spatially structured correlation is quite significant in cases of crashes involving minor injury or PDO and that unstructured effects are somewhat significant at the intersection-level for cases of severe-injury crashes.
Influence of Driver Distractions on the Likelihood of Rear-End, Angular, and Single-Vehicle Crashes in Missouri
Authors: Ghazizadeh Mahtab , Boyle Linda Ng
Published: January 2010

Driver distraction has been associated with a higher likelihood of crash involvement. Crash data from the state of Missouri for the years 2001 to 2006 revealed that the highest number of distraction-related crash incidents occurred while drivers were using cell phones or other electronic devices or had passengers in the car. A multinomial logit model was used to predict the odds that a driver with a specific type of distraction would be involved in one of the most frequent crash types, rear-end, angular, or single-vehicle collision, in comparison with each other. Results showed that distractions could have varying influences on crash type. More specifically, passenger-related and cell phone distractions are more likely in angular crashes; for other electronic device–related distractions, the most probable type of crash is a single-vehicle crash. Inferences made in this study should be considered in light of the fact that the data were limited in the number of reported distractions and the study was conducted in only one state. Future research comparing similar distraction factors across other states and nationally may provide a broader view of the type and severity of crashes related to driver distractions.
Impact of Incremental Increases in Cognitive Workload on Physiological Arousal and Performance in Young Adult Drivers
Authors: Mehler Bruce , Reimer Bryan , Coughlin Joseph F. , Dusek Jeffery A.
Published: January 2010

This study examined the sensitivity of heart rate, skin conductance, and respiration rate as measures of mental workload in a simulated driving environment. Workload was systematically manipulated by using increasingly difficult levels of a secondary cognitive task. In a sample of 121 young adults, heart rate increased incrementally with increasing task demand. Significant elevations in skin conductance and respiration rate were also observed. At the lower levels of added workload, secondary task performance was nearly perfect and changes in indices of driving performance were negligible. At the highest level of workload, all three physiological measures appeared to plateau, and a subtle drop in simulated driving performance became detectable. Taken together, the pattern of results indicates that physiological measures can be sensitive to changes in workload before the appearance of clear decrements in driving performance. These findings further highlight a role for physiological monitoring as a means to measure mental workload in product design and functionality research. They also support work exploring the potential for incorporating physiological measures of driver workload and attentional state in future safety systems.
Impact of Cognitive Task Complexity on Drivers’ Visual Tunneling
Authors: Reimer Bryan
Published: January 2010

Cognitive distractions have been shown to affect drivers adversely and are a leading cause of accidents. Research indicates that drivers alter how they allocate their visual attention while engaging in secondary cognitive tasks. To evaluate the potential impact of secondary cognitive tasks on the allocation of drivers’ visual attention and on vehicle control, drivers were presented with increasingly complex forms of an auditory cognitive task while driving an instrumented vehicle. Measures of vehicle performance and eye gaze were assessed. Consistent with theories of visual tunneling, gaze distributions were significantly smaller while drivers performed certain levels of the secondary task; peripheral vision was thereby reduced. During the most difficult level of the secondary task, gaze dispersion was smaller than during any other level of the task. Changes in visual attention may provide earlier indications of cognitive distraction than changes in vehicle control, the latter of which were observed only during the most difficult level of the secondary task. Observed changes in vertical eye position suggest that drivers compensate for moderate cognitive demands by increasing their sight distance before further incremental increases in workload exceeded their abilities. In summary, the workload of a secondary cognitive task affected drivers’ visual attention. A low to moderate increase in workload was detectable as a change in gaze before vehicle control suffered. Gaze restriction appears related to the degree of cognitive workload. This work shows that visual attention is a potential method of detecting changes in driver state associated with cognitive workload.
Effects of Cognitive and Perceptual Loads on Driver Behavior
Authors: Redenbo Seth J. , Lee Yi-Ching
Published: January 2010

The objective of the study was to examine how cognitive and perceptual loads affect driving strategies and the guidance of attention. A cue–target search task was implemented, and two experiments manipulated prioritization of a primary task and working memory load (Experiment 1) and congruence and salience of targets (Experiment 2). The cues and non-target distracters in the environment were designed to influence discriminability and predictability of target locations (e.g., target pedestrians or target squares). Driving-related variables along with reaction times and accuracy scores were collected. The load theory of attention was used as a framework for the design of the experiments. The study was designed to expand the findings of load theory research to a more realistic driving environment and identify how drivers strategized in conditions of cognitive and perceptual loads. In line with previous studies, both experiments found better lane control during the dual-task period when compared with single-task performance. The other driving results showed detrimental effects of performing secondary tasks while driving. In Experiment 1, prioritization increased target accuracy while decreasing reaction times. In Experiment 2, high salience of targets increased accuracy, but curiously increased reaction times for target detection. Although some results were not as expected, the perceptual load manipulation had an overall negative effect on visual search. In-vehicle interfaces could benefit by incorporating designs that do not exhaust drivers’ working memory or distract them with complex displays.
Immediate Recall of Driver Warnings in Forward Collision Warning Scenarios
Authors: Curry Reates , Blommer Mike , Greenberg Jeff , Tijerina Louis
Published: January 2010

This paper describes driver recall performance for a forward collision warning (FCW) alert immediately after a critical lead vehicle braking event. A sample of 120 younger and older test participants, balanced by gender, participated in a study of alternative FCW alerts in the Ford Motor Company VIRTTEX driving simulator. A baseline group of participants received no FCW support. Each of the other participants experienced one and only one FCW alert type, visual, auditory, or both. Half of the participants who received an FCW alert had been given knowledge that such a system was in the test vehicle, and half of the participants had been told nothing. A digit-reading distraction task was presented repeatedly during the test drive. The last repetition of this task coincided with the lead vehicle braking event and FCW. Immediately after the event, test participants were asked if they had received a warning and, if so, what they recalled about it. Results were analyzed for those 93 warned test participants who interrupted the digit-reading task to respond to the FCW alert. Approximately 26% of these test participants did not remember receiving a warning at all. Only 58% of the test participants who recollected a warning could accurately recall its modality in all its details, although nearly 90% of those who received the combined audio and video warning recalled at least one of the modalities correctly. Those who received FCW information before the drive had significantly greater recollection than those who were not given any FCW a priori information. Age and gender differences were not statistically significant. The implications of these results are discussed.
Conventional versus Moving-Map Navigation Methods
Authors: Antin Jonathan F. , Stanley Laura M. , Cicora Kathleen F.
Published: January 2010

Thirty-eight male and female participants, aged 21 to 50 years, drove to three unfamiliar destinations using three different methods of navigation: Nav, an in-vehicle moving-map and route guidance navigation system; Free, the free use of paper maps or computer printouts, but without access to the navigation system; and Way, which was the same as Free, but with waypoints also provided. Each participant had a minimum of 6 weeks of prior experience using in-vehicle navigation technology. The routes were each designed to sample urban, rural, and highway road categories. Methods were counterbalanced across route and presentation order. An onboard experimenter administered the study. Data were gathered to assess navigational efficiency, workload, and safety-related driving errors. A peripheral detection task was included as a loading task to measure workload and spare attentional capacity objectively; the rating scale of mental effort was included as a subjective measure of mental effort. Use of the navigation system produced better results than either of the two conventional methods in terms of several key metrics related to driver workload, driving errors, and navigational efficiency. These results support the notion that an onboard, moving-map navigation system incorporating route guidance can play a meaningful role in enhancing navigational efficiency and safety for experienced navigation system users. Future research is recommended to examine eye glance and other driver behaviors further, such as lane excursions and headway maintenance, to gain additional insight into the effect of method of navigation on the primary driving task.
Driving Behaviors, Risk Perceptions, and Stress
Authors: Mitra-Sarkar Sheila , Andreas Marie
Published: January 2010

In an effort to examine the driving behaviors of military personnel, this study surveyed 469 marines. These military personnel were stationed in California; more than half reported recently returning from deployment overseas. During base stand downs, the marines were given a survey that asked them to report on various previous driving behaviors, perceptions of aggressive or risky driving actions, and perceived stress. Participants who reported recent deployment to a fighting zone (Iraq) reported significantly higher scores on items such as being a risk taker, losing their temper while driving, and the right to retaliatory action against aggressive actions from other drivers. The results of this study indicate a need for further examination of the driving habits of military personnel as well as a closer exploration of risk-taking behaviors of personnel recently returned from combat zones.
Assessing and Influencing Driver Attitudes in the United Kingdom
Authors: Johnson Charles , Lewis Jill , Thew Rosemary
Published: January 2010

Accident and injury rates among car drivers have been consistently decreasing in the United Kingdom since 1994. The United Kingdom now has one of the lowest accident rates in the world. However, it is unclear to what extent this improvement is because of improvements in car and road design and legislation rather than improvements in driver behaviors. Indeed, although rates have decreased overall, among young and novice drivers they have been increasing. Driver attitudes are thought to underlie this trend and to constrain further improvements in the overall accident rate. Attitudes that affect driving performance have been explicitly included in the driver competency framework that now forms the basis of the United Kingdom's approach to driver training, assessment, and licensing. As part of these developments, the Driving Standards Agency commissioned Competence Assurance Solutions Ltd. to develop and evaluate an attitude assessment questionnaire, the Attitude Advisor, primarily for use with trainee drivers but potentially with other groups of drivers as well. The questionnaire's design is based on Ajzen's theory of planned behavior and a taxonomy of driver attitudes related to safety. Findings from trials of the prototype questionnaire provide support for the underlying theory and evidence for its criterion-related validity. In particular, scores on the questionnaire are related to age, gender, accident record, and driving convictions. This paper outlines options for how the Attitude Advisor may be used as part of driver training and personal development in the United Kingdom.
Intrafamilial Transmission of Driving Behavior
Authors: Prato Carlo Giacomo , Lotan Tsippy , Toledo Tomer
Published: January 2010

This study analyzes intrafamilial transmission of driving behavior by examining driving patterns of newly licensed young drivers and their family members as recorded over a period of 9 months using in-vehicle data recorders. Various maneuvers that the drivers undertook were identified in the measurements and used to compute risk indices for each driver during each month. The correlations between risk indices of drivers within the same family were studied. The results show intrafamilial transmission of driving behavior and reveal that this transmission evolves over time, as the behavior of young drivers is initially more closely related to that of their family members but gradually develops into a more differentiated personal driving style. Higher correlations are also found for specific maneuver types, such as braking and accelerating, and to a lesser extent for other maneuvers, such as speeding. The findings of the study indicate a need to carefully consider the role played by parents in the driving education of young adults and advising parents to exert control over their offspring's driving through positive modeling, and not only through well-designed commentary during driving.
Evaluation of Signs and Markings for Partial Continuous Flow Intersection
Authors: Inman Vaughan W.
Published: January 2010

The continuous flow intersection (CFI) supports high traffic flow where there is a large volume of left turns. The CFI accomplishes this by moving left-turning traffic to the left side of a highway before the main intersection. Left turns can then be made at the same time as the opposing through movement. This eliminates the need for separate left turn signal phasing and reduces the potential conflict points between left-turning and through traffic. Because CFI left turn movements begin well in advance of the road junction, signing and marking requirements are different from those for conventional intersections. This study reports the results of a driving simulator study that compared alternative signing and marking options. Three strategies for navigation signing in advance of the crossover were evaluated: overhead signing and two different ground-mounted sign alternatives. In addition, on a leg of the CFI that did not cross left-turning traffic to the left side of the roadway, alternative schemes for emphasizing the location of the stop line were evaluated. The results showed that the ground-mounted navigation signing treatment that included a “Keep Left” advance sign was as effective as an overhead navigation sign. All treatments for designating the stop line were equally effective.
Modeling the Role of Transportation Information in Mitigating Major Capacity Reductions in a Regional Network
Authors: Hu Hyejung , Williams Billy M. , Rouphail Nagui M. , Khattak Asad J. , Zhou Xuesong
Published: January 2010

A practical method is presented for systematically evaluating the network impacts of advanced traveler information systems (ATISs) to support well-informed project decisions and well-founded funding priorities. Detailed comparative assessments of available evaluation tools are given on the basis of a common set of desirable criteria. A mesoscopic network modeling and dynamic traffic assignment (DTA) tool, namely, DYNASMART-P, was identified as a promising candidate model and was applied to the evaluation of case study scenarios in a subnetwork of the Triangle Regional Model in North Carolina. The case study involved planned work zone activities occurring during nonpeak time periods. The case study demonstrated that the DYNASMART-P DTA tool is capable of providing reasonable evaluation results, including realistic estimates of the effectiveness of ATISs in mitigating the congestion caused by work zone activities. The case study analyses further illustrated the high value of traveler information through an example benefit–cost analysis based on the scenario modeling. The simulation results were validated for reasonableness through comparison with field speed data. Finally, several potential DTA functionality enhancements are identified that will further support ATIS evaluation.
Role of Dynamic Information in Supporting Changes in Travel Behavior
Authors: Wang Xin , Khattak Asad J. , Fan Yingling
Published: January 2010

Travelers can often benefit from acquiring relevant information on their intended modes and routes. By providing pretrip and en route information, advanced traveler information systems present real opportunities for improving the travel experience of individuals and increasing efficiency of the transportation system. In this regard, it is important to understand how consumers acquire and respond to travel information. This study develops a conceptual framework identifying important factors influencing travelers’ information acquisition behavior and their response to dynamic information. The model is empirically tested with the use of a recent and comprehensive regional travel survey. A sample selection model is estimated to be consistent with the two-stage processing of travel information (i.e., acquisition and response). Results show that information acquisition and changes in travel plans are sensitive to different sets of factors. In the data set analyzed, normal travel time to work is found to be a critical factor in information acquisition, but has an insignificant association with the change of travel plans. Furthermore, travelers respond differently to various information technologies. In an examination of change behavior (including route change, mode change, and trip cancellation), Internet access had the strongest association with change. With examination of specific route change behavior, transportation information obtained through radio had the strongest association with change. The study generates useful implications on how to improve existing and future traveler information systems.
Methodology to Analyze Adaptation in Driving Simulators
Authors: Sahami Saeed , Jenkins Jacqueline M. , Sayed T.
Published: January 2010

Adaptation to a driving simulator is one of the necessary conditions for the validity of almost all driving simulator studies. Learning how to control a simulated vehicle requires practice, which will put some mental load on drivers and can distract them from their main task (i.e., driving). Such distraction during the learning phase affects drivers’ reactions to different situations compared with what they would have done in the real world; therefore, having a tool to confirm that adaptation occurred is necessary to have accurate data. This methodology needs to be sensitive to the diversity of driving styles and applicable to a variety of driving tasks and performance measures. A comprehensive review of the literature indicated a general deficiency in the methodologies being used. Common approaches include having participants drive for a predefined time or driving distance or drive until the participants report that they feel comfortable. Such approaches do not ensure that adaptation has indeed occurred. This paper proposes a methodology to evaluate adaptation by analyzing driver performance measures. The methodology is based on the concept of experience curve effect and is intended to complete and further develop the idea of the learning curve effect that was used in the authors’ earlier research. The methodology was tested for adaptation to acceleration and braking tasks using UBCDrive driving simulator. The results indicated that experience and learning curve effects can be used to identify adapted, adapting, and nonadapting participants.
Effect of Headlight Swivel Angle on Driver Behavior to Avoid Conflict with Pedestrians Approaching from the Right
Authors: Hagiwara Toru , Hamaoka Hidekatsu , Tabata Yousuke , Morishita Masahiko
Published: January 2010

In Japan, where vehicles travel on the left side of the road (i.e., right turns correspond to left turns in the United States), right turns have the potential to make drivers’ workloads heavy at intersections, because the driver has to judge the headway in oncoming traffic while avoiding pedestrians in the crosswalk. Few investigations have addressed measures for avoiding conflicts with pedestrians in the crosswalk. This study proposes a headlight that is designed to swivel rightward during right turns to illuminate pedestrians coming from the right. The authors conducted a field experiment to determine whether the swivel angle conditions affected drivers’ responses. Drivers’ avoidance behavior does not differ greatly among the three swivel angles. However, from the results of the braking position after the vehicle started turning right, the swivel angle increases the distance between the conflict point on the crosswalk and the braking position of the right-turning vehicle. The driver could estimate the time lag early and accurately while turning right as the swivel angle increases.
Impact of Narrower Lane Width
Authors: Rosey Florence , Auberlet Jean-Michel , Moisan Olivier , Dupré Guy
Published: January 2010

This driving simulator study investigated differences in the influence of lane width reduction on speed profiles and lateral positions in real-world and simulator conditions. The use of driving simulators has been expanding in transportation research. This use raises the question of the simulators’ validity. The study was developed in two steps. In the first step, an experiment was conducted with the INRETS (French National Institute for Transport and Safety Research) driving simulator. Forty-three drivers drove in the simulator. Two configurations of lane widths (3.5 m and 3 m) were tested, both chosen in reference to a previous French field study carried out on a rural road to assess the impact of lane width reduction and the provision of a hard shoulder on driver behaviors (speed, lateral positioning). In the second step, results were compared with the results of the French field study. The comparison showed that, as in the field study, reducing the lane width had no impact on speeds but did induce the participants to drive closer to the center of the road. It also showed that oncoming vehicles induced subjects to move toward the right side of their lanes. Finally, the results showed a relative behavioral validity.
Can Driving Simulators Contribute to Solving Critical Issues in Geometric Design?
Authors: Bella Francesco
Published: January 2010

Research on driving simulation in virtual reality has not been recommended by strategic documents for solving critical issues in geometric design. However, several research efforts have demonstrated the usefulness of driving simulators in road design. The objective of this paper is to initiate a discussion on the effective contribution of driving simulators to issues of geometric design. The paper gives an overview of the main experiences acquired in geometric design using advanced driving simulators and points out their potential as well as their limits. It then outlines the critical issues in promoting their use in geometric design and provides recommendations for overcoming these issues.
Dots & Dashes
Authors: Hacker Joseph F. , Krykewycz Gregory R. , Meconi Jane M.
Published: January 2010

Dots & Dashes is a program that condenses the long-range public transit planning process, with its financial constraints, trade-offs, and land use considerations, into an outreach activity (a board game) appropriate for a range of stakeholder audiences from lay citizens to transportation professionals. By playing Dots & Dashes, stakeholders express their preferences for public transit investments and are educated about the planning process through group negotiation. Dots & Dashes was designed as a self-contained and branded package that would be replicable by planners in other regions. In the Delaware Valley Regional Planning Commission (DVRPC) region, the program's aggregated results inform DVRPC's long-range plan as well as a new long-range vision for transit. Dots & Dashes was designed to be transferable for application in other cities and regions. In the simplest terms, planners interested in replicating the exercise need only adjust the scale of the game board and game pieces to match the local area and scale costs as necessary to account for different time horizons or local project costs.
Visual Analytics for Transportation Incident Data Sets
Authors: Wongsuphasawat Krist , Pack Michael L. , Filippova Darya , VanDaniker Michael , Olea Andreea
Published: January 2010

Transportation systems are being monitored at an unprecedented scope, which is resulting in tremendously detailed traffic and incident databases. Although the transportation community emphasizes developing standards for storing these incident data, little effort has been made to design appropriate visual analytics tools to explore the data, extract meaningful knowledge, and represent results. Analyzing these large multivariate geospatial data sets is a nontrivial task. A novel, web-based, visual analytics tool called Fervor is proposed as an application that affords sophisticated, yet user-friendly, analysis of transportation incident data sets. Interactive maps, histograms, two-dimensional plots, and parallel coordinates plots are four featured visualizations that are integrated to allow users to interact simultaneously with and see relationships among multiple visualizations. Using a rich set of filters, users can create custom conditions to filter data and focus on a smaller data set. However, because of the multivariate nature of the data, finding interesting relationships can be a time-consuming task. Therefore, a rank-by-feature framework has been adopted and further expanded to quantify the strength of relationships among the different fields describing the data. In this paper, transportation incident data collected by the Maryland State Highway Administration's CHART program are used; however, the tool can be easily modified to accept other transportation data sets.
Methodology for Counting Pedestrians at Intersections
Authors: Schneider Robert J. , Arnold Lindsay S. , Ragland David R.
Published: January 2010

Accurate methods of counting pedestrians are needed to quantify exposure for safety analysis, rank infrastructure improvements and safety programs by priority, evaluate the benefits of pedestrian projects, develop models of pedestrian volumes, and track changes in pedestrian activity over time. However, pedestrian counts are still much less common than motor vehicle counts in most communities. In addition, existing count methodologies are not standardized and rarely provide enough information to extrapolate to weekly, monthly, or annual volumes. This exploratory study presents a methodology for estimating weekly pedestrian intersection crossing volumes based on 2-h manual counts. The methodology, implemented in Alameda County, California, involves a combination of manual and automated counts to determine weekly volumes. More than 690,000 pedestrians were counted during the 13-week study period. Manual counts were conducted at a set of 50 intersections. Automated counts from sidewalk locations in close proximity to a subset of 11 intersections were used to adjust these counts for time of day and week, surrounding land use characteristics, and weather conditions. The extrapolated pedestrian volume estimates were then used to calculate the number of reported crashes per 10 million pedestrian crossings at each of the study intersections. The results of this study demonstrate how pedestrian volumes can be routinely integrated into transportation safety and planning projects.
Pilot Model for Estimating Pedestrian Intersection Crossing Volumes
Authors: Schneider Robert J. , Arnold Lindsay S. , Ragland David R.
Published: January 2010

Better data on pedestrian volumes are needed to improve the safety, comfort, and convenience of pedestrian movement. This data collection requires more carefully developed methodologies for counting pedestrians as well as improved methods of modeling pedestrian volumes. The methodology used to create a simple pilot model of pedestrian intersection crossing volumes in Alameda County, California, is described. The model is based on weekly pedestrian volumes at a sample of 50 intersections with a wide variety of surrounding land uses, transportation system attributes, and neighborhood socioeconomic characteristics. Three alternative model structures were considered, and the final recommended model has a good overall fit (adjusted R2 = .897). Statistically significant factors in the model include the total population within a 0.5-mi radius, number of jobs within a 0.25-mi radius, number of commercial retail properties within a 0.25-mi radius, and the presence of a regional transit station within a 0.1-mi radius of an intersection. The model has a simple structure, and it can be implemented by practitioners using geographic information systems and a basic spreadsheet program. Because the study is based on a relatively small number of intersections in one urban area, additional research is needed to refine the model and determine its applicability in other areas.
Effectiveness of Automatic Pedestrian Detection Device and Smart Lighting for Pedestrian Safety
Authors: Nambisan Shashi S. , Pulugurtha Srinivas S. , Vasudevan Vinod , Dangeti Mukund R. , Virupaksha Vinay
Published: January 2010

A summary is given of an evaluation of the effectiveness of an automatic pedestrian detection device and a smart lighting system in improving pedestrian safety. These countermeasures were deployed at a midblock location in the Las Vegas metropolitan area in Nevada. The evaluations are based on field observations of pedestrian and motorist behaviors before and after the installation of the countermeasures. Their effectiveness was evaluated by using the following measures: percentage of pedestrians who looked to their left and right before and while crossing, percentage of pedestrians who changed their course of action, percentage of pedestrians trapped in the middle of the road, percentage of motorists who yielded to pedestrians, distance from the crosswalk at which motorists yielded to pedestrians, and delays. The results show an increase in pedestrians’ observational behavior and an improvement in motorists’ yielding behavior. A reduction in the number of pedestrians trapped in the roadway was also observed. Overall, the installation of the automatic pedestrian detection device and the smart lighting showed positive safety benefits for motorists’ and pedestrians’ behaviors at the test location. The findings from this study could be used to enhance pedestrian safety on arterial roads in other cities with similar demographic characteristics and traffic conditions.
Assessing Impact of Weather and Season on Pedestrian Traffic Volumes
Authors: Aultman-Hall Lisa , Lane Damon , Lambert Rebecca R.
Published: January 2010

Twelve months of automated hourly pedestrian counts in downtown Montpelier, Vermont (population 8,035), were analyzed along with weather data (temperature, relative humidity, precipitation, and wind) to determine the factors affecting count variability. This study is unique in that a large amount of data in a single location was collected in a locale with an extreme range of weather conditions. Results indicate consistent patterns in relative volumes by hour of the day and month of the year that show that good adjustment factors can be developed to use with time-limited counts to estimate usage and pedestrian exposure to accidents. Predictive relationships were found between weather variables, season, and pedestrian volumes (30% of the variation is accounted for). Consistent hourly patterns within a day and the consistency of day type (weekday or Saturday versus holiday or Sunday) suggest that correction factors and forecasting methods are feasible for pedestrian traffic volumes. The results indicate that weather such as cold temperatures or precipitation consistently reduces aggregate levels of walking by only a moderate amount (less than 20%). Precipitation and season are found to affect pedestrian levels even when time of day and day of week are controlled, but other, larger, unmeasured factors are at play.
Automated Analysis of Pedestrian–Vehicle Conflicts Using Video Data
Authors: Ismail Karim , Sayed Tarek , Saunier Nicolas , Lim Clark
Published: January 2010

Pedestrians are vulnerable road users, and despite their limited representation in traffic events, pedestrian-involved injuries and fatalities are overrepresented in traffic collisions. However, little is known about pedestrian exposure to the risk of collision, especially when compared with the amount of knowledge available for motorized traffic. More data and analysis are therefore required to understand the processes that involve pedestrians in collisions. Collision statistics alone are inadequate for the study of pedestrian–vehicle collisions because of data quantity and quality issues. Surrogate safety measures, as provided by the collection and study of traffic conflicts, were developed as a proactive complementary approach to offer more in-depth safety analysis. However, high costs and reliability issues have inhibited the extensive application of traffic conflict analysis. An automated video analysis system is presented that can (a) detect and track road users in a traffic scene and classify them as pedestrians or motorized road users, (b) identify important events that may lead to collisions, and (c) calculate several severity conflict indicators. The system seeks to classify important events and conflicts automatically but can also be used to summarize large amounts of data that can be further reviewed by safety experts. The functionality of the system is demonstrated on a video data set collected over 2 days at an intersection in downtown Vancouver, British Columbia, Canada. Four conflict indicators are automatically computed for all pedestrian–vehicle events and provide detailed insight into the conflict process. Simple detection rules on the indicators are tested to classify traffic events. This study is unique in its attempt to extract conflict indicators from video sequences in a fully automated way.
Reduction of Pedestrian Fatalities, Injuries, Conflicts, and Other Surrogate Measures in Miami–Dade, Florida
Authors: Ellis Ralph , Van Houten Ron
Published: January 2010

The purpose of this study was to identify and evaluate measures to reduce pedestrian deaths and injuries along high-crash corridors in Miami–Dade County, Florida, by targeting engineering countermeasures toward specific high-crash locations and zones. With pedestrian crash data from 1996 to 2006, eight corridors were identified within the county as having abnormally high numbers of pedestrian crashes. On the basis of crash characteristics, 14 different engineering treatments were implemented to reduce pedestrian crashes along the specific corridors. A before-and-after study was used to compare the sequential implementation of a 3-year large-scale NHTSA project that focused primarily on education and enforcement components followed by a large-scale FHWA engineering countermeasure project that was added to the NHTSA project along specific corridors. Results showed that the NHTSA pedestrian safety project reduced countywide pedestrian crash rates by 13.3% along the targeted corridors, and the FHWA engineering safety project produced a further reduction to 49.5% of the baseline level. These results translate to 50 fewer pedestrian crashes annually along the treated corridors.
Pedestrian Crosswalks at Midblock Locations
Authors: Lu George (Xiao-Zhao) , Noyce David A.
Published: January 2010

The increasing number of midblock vehicle–pedestrian crashes has led traffic engineers to consider safer treatments for pedestrian crossings while preserving flow efficiency. One of the existing solutions is to install signalized crosswalks. Using a microsimulation approach, this study first assesses three signal systems for a typical midblock crosswalk (MBC) with varied geometries, with the aim to explore how different signalization schemes and crosswalk geometries affect measures of effectiveness from all user perspectives. The results indicate that two-phase timing outperforms one-phase timing and the innovative high-intensity activated crosswalk significantly improves vehicle operations over actuation by pedestrians and pedestrian light control. Of existing signals, the pedestrian user-friendly interface (PUFFIN) is more functional because of its dynamic pedestrian clearance interval, but it still does not account for enough safety and human factors in its control logic and thus lacks an adaptive ability in fulfilling competing objectives. Fuzzy logic control (FLC) has proved effective for a complex optimization problem with multiple goals, uncertain information, and vague decision criteria. Traffic signal timing lies in this realm. To model the range of variables affecting MBCs, a user-friendly FLC counterpart is developed and then evaluated against PUFFIN to quantify potential safety and efficiency benefits. The results show that with straightforward logic and tractable parameters, FLC manages the MBC signal timing effectively and outperforms PUFFIN in terms of a compromise among enhanced safety, ameliorated operations, and lessened social cost from crashes and delays.
Pedestrian Scramble Operations
Authors: Kattan Lina , Acharjee Shanti , Tay Richard
Published: January 2010

The City of Calgary, Alberta, Canada, has implemented a pilot test of the pedestrian scramble operation (also known as the Barnes dance) at two intersections in the downtown area. Pedestrian scramble is an exclusive pedestrian signal phase in which traffic in all four directions is stopped and pedestrians are allowed to make diagonal as well as lateral crossings. The purpose of this study is to evaluate the pilot project at one intersection to determine the effect of this new operation on pedestrian safety. Because of the absence of pedestrian–vehicle crashes in this study, the number of pedestrian conflicts was used as a surrogate measure of safety. Field observations were made 6 weeks after the implementation of the scramble operation. Two Poisson regression models were developed to model the number of conflicts and violations. The results showed that the number of pedestrian–vehicle conflicts decreased significantly but the number of pedestrian violations increased significantly after implementation of the scramble operation. The analysis also revealed that 13% of the total violations were “safe side” crossings (concurrent with the vehicle movement), 2% of the violations were “unsafe side” crossings, and about 40% of the total violations were at the beginning of the flashing “Don't Walk” phase (within 2 to 3 s) and persons were able to cross safely within the pedestrian phase. A survey was also conducted to monitor public perception, and the results showed a generally positive attitude toward this new signal operation. It is recommended that the operation be monitored over time and evaluated again.