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192 pages

Objective: Determine the effects of BMI on the risk of serious???to???fatal injury (Abbreviated Injury Scale ??? 3 or AIS 3+) to different body regions for adults in frontal, nearside, farside, and rollover crashes. Design and Methods: Multivariate logistic regression analysis was applied to a probability sample of adult occupants involved in crashes generated by combining the National Automotive Sampling System (NASS???CDS) with a pseudoweighted version of the Crash Injury Research and Engineering Network database. Logistic regression models were applied to weighted data to estimate the change in the number of occupants with AIS 3+ injuries if no occupants were obese. Results: Increasing BMI increased risk of lower???extremity injury in frontal crashes, decreased risk of lower???extremity injury in nearside impacts, increased risk of upper???extremity injury in frontal and nearside crashes, and increased risk of spine injury in frontal crashes. Several of these findings were affected by interactions with gender and vehicle type. If no occupants in frontal crashes were obese, 7% fewer occupants would sustain AIS 3+ upper???extremity injuries, 8% fewer occupants would sustain AIS 3+ lower???extremity injuries, and 28% fewer occupants would sustain AIS 3+ spine injuries. Conclusions: Results of this study have implications on the design and evaluation of vehicle safety systems.

131 pages

We compared system performance and driver opinion of 3 in-vehicle navigation aids - two advanced traveler information systems (ATISs; Ali-Scout and TetraStar) and written instructions - when used on the road concurrently under identical conditions. Few drivers in the study had difficulty finding initial routes or became lost. Users of Ali-Scout, an ATIS that utilizes traffic information in routing, drove longer-distance routes, got lost more frequently, and gave their system less positive ratings than did TetraStar users. Users of the 2 ATISs traversed routes that were significantly shorter in duration than those driven by users of written instructions. The time savings benefit of the advanced technology systems over written instructions was greatest during peak traffic conditions. Drivers who were familiar with the road network, overall, had less difficulty finding destinations and drove shorter-duration routes than drivers who were unfamiliar with the road network. Actual or potential applications of this research include improving the design of technologies that provide navigation assistance to travelers.

This study compared the quantitative influence of a variety of factors on the performance of low-beam headlamps. The factors included were vertical aim, horizontal aim, mounting height, lateral separation, lens dirt, lamp voltage, number of functioning lamps, vehicle type, beam pattern and light source. The following aspects of headlamp performance were considered: visibility of pedestrians, visibility of road delineation, visibility of vehicle reflex reflectors, visibility of rettoreflective traffic signs, visibility of targets near the road expansion point, glare directed towards oncoming drivers, glare reflected from wet pavement towards oncoming drivers, glare directed towards rearview mirrors of preceding vehicles, and foreground illumination. A sales-weighted average US beam pattern, with lamps mounted at sales-weighted average locations, formed the basis for most of the analyses. The results indicate that, from among the factors studied, vertical aim is overwhelmingly the most important factor in influencing the performance of low-beam headlamps. The second most important factor is the number of functioning lamps. The main implication of this study is that major improvements in current (fixed as opposed to adaptive) low-beam headlighting could be achieved primarily by better control of vertical aim and by use of longer-life headlamps.

This study evaluated the effects of voltage changes on beam patterns of low-beam headlamps. Seven different types of filament lamps were tested. The voltages used were 12.0, 12.8 and 13.5V. The photometry was performed from 20?? left to 20?? right, and from 5?? down to 5?? up, all in steps of 0.5??. The main finding of this study is that, for all seven lamps tested, voltage changes between 12.0V and 13.5V caused light output to change by the same proportion throughout the beam pattern. Therefore, for filament lamps, it is reasonable to use a single constant for all values in a beam pattern when converting a headlighting specification at one voltage to a specification at a different voltage, at least if the voltages in question are between 12.0 V and 13.5 V. The constants obtained across the seven lamps tested were similar to each other. Furthermore, these constants were in general agreement with the constants derived using the standard IES formula relating light-output changes to voltage changes.

The amount of light reflected from a retroreflective traffic sign decreases with an increase in the observation angle???the angle between the headlamp, the sign, and the eyes of the driver. Mainly because of the increased seated eye height of truck drivers, the actual observation angles are greater for them than they are for car drivers. Consequently, there is concern about the impaired night-time detection and legibility of retroreflective signs for truck drivers. The present study evaluated the relative amount of light reaching drivers of different types of vehicle by using survey data collected in 1989 by the Transport and Road Research Laboratory (TRRL) in England. The TRRL data included driver eye heights and headlamp mounting heights for 445 vehicles. The present analysis considered three sign locations on a straight roadway: left shoulder, centre, and right shoulder. Two viewing distances were included: 152 m (500 feet) (typical of a sign-legibility distance), and 305 m (1000 feet) (typical of a sign-detection distance). The analysis considered both the differential amount of illumination impinging on the signs from headlamps of trucks and cars, as well as the differential amount of the light reflected from the signs in the direction of truck drivers and car drivers. The main results are that for the viewing distance of 152 m, the amount of light reaching a truck driver can be as low as 25% of the light reaching a car driver; the corresponding percentages for the viewing distance of 305 m are as low as 68%. These reductions were then related to the expected effects on sign legibility and detection. The results imply that the increased eye height of truck drivers could have a major effect on the legibility of retroreflective traffic signs, but only a modest effect on their detection.

This laboratory study evaluated the effect of the size of the glare source on discomfort glare. The subjects performed two simultaneous tasks: continuous compensatory tracking, and evaluation of discomfort from glare stimuli presented periodically in the near visual periphery. The glare stimuli were circles of two sizes (approximately 0.3 and 0.6?? in diameter), and produced five illuminance levels (from 0.03 to 3.1 lux) at the observer's eye. Subjects used a nine-point response scale to evaluate discomfort glare. The results indicate that there was a small but statistically significant effect of the size of glare source, with the smaller glare stimuli resulting in more discomfort glare. The mean difference over the range of glare illuminances tested was 0.2 points on the nine-point response scale.

This study evaluated the effects of voltage on rise time and light output from incandescent brake lamps for a range of voltages representing realistic values for large trucks. The findings indicate that, relative to nominal voltage of 12.8 V, realistic voltages for large trucks lead to significant increases in rise time and to decreases in light output. At 9 V, for example, 90% of the asymptotic light output is reached about 113 ms later than at 12.8 V, and the asymptotic light output is about 28% of the output at 12.8 V. Analogous comparisons of 6 V with 12.8 V indicate an increase in the rise time to 90% of asymptotic light output of about 316 ms and a decrease in asymptotic light output to about 5%. The changes obtained in rise time and light output of incandescent lamps as a function of voltage are of practical importance because they can be expected to increase following drivers' reaction times to brake signals and to increase the frequency of missed signals.

This study evaluated subjects' impressions of performance of high-intensity discharge (HID) headlamps after in-traffic experience, with an emphasis on colour appearance of red stop signs. In the first of two tasks, subjects drove (or rode) for half an hour on a variety of roads in a car equipped with either HID or tungsten-halogen low-beam headlamps. Instructions did not mention colour appearance. The second task involved a direct comparison of HID and tungsten-halogen headlamps. In this task, subjects drove (or rode) twice along a 7-minute route in a residential area, and they were instructed to pay attention to the colour appearance of stop signs and other objects. The main finding from Task 1 is that subjects who experienced HID headlamps did not report more (or fewer) spontaneous negative comments on colour appearance of stop signs or other objects than did subjects who experienced tungsten-halogen headlamps. Furthermore, the evaluations of the overall performances of the two types of headlamps were not different. In the direct comparison of Task 2 there was no evidence of problems with colour appearance when using HID headlamps. Moreover, subjects preferred HID headlamps in terms of the overall performance, and in making stop signs and other objects stand out from their background. However, this preference for HID headlamps was present only for subjects who had the relatively extended exposure to the HID headlamps in Task 1. The present results provide no evidence for problems with colour appearance of stop signs and other objects when using HID headlamps. Furthermore, the study provides evidence that observers perceive HID headlamps as helping stop signs and other objects to stand out from their background. The results imply that given a somewhat extended exposure to HID headlamps, drivers would prefer them over current tungsten-halogen headlamps.

The research designs, develops, validates, and applies an exposure model of productivity-permitted general freight trucking on uncongested highways. Productivity-permitted general freight trucks (long trucks) are multiple trailer configurations, consisting of van trailers, which exceed basic vehicle length limits but operate within basic weight restrictions. The three predominant long trucks in North America are Rocky Mountain doubles (Rockies), Turnpike doubles (Turnpikes), and triple trailer combinations (triples). Long trucks have been used in Canada since the late 1960s. Recent highway investments in the Canadian Prairie Region have effectively completed the network on which long trucks are allowed to operate. Despite widespread use of long trucks for many years and these recent infrastructure investments, there is a knowledge deficiency about long truck exposure. The research uses the transportation systems analysis approach to design, develop, and validate the long truck exposure model. Exposure is expressed as an explanatory variable in three principal dimensions (volume, weight, and cube), which is needed for predicting transportation system impacts of long truck operations. The research applies the model to clarify issues that should be considered in establishing charges for long truck permits, determining long truck safety performance, and developing load spectra for long trucks. The exposure model relies on a unique dataset that integrates output from a classification algorithm, field observations, and industry intelligence. The results indicate that long trucks travelled 67 million kilometres on a 10,000 centreline-kilometre highway network in the Canadian Prairie Region in 2006. The model demonstrates strong temporal and geographic concentration of long truck travel on the network. Application of the results reveals the following findings: • Decisions about establishing long truck permit charges are supported by consideration of options within a revenue

Crash injury reduction via lap-shoulder belt use has been well documented. Like any other interior car component, lap-shoulder belts may be related to injury in certain crashes. Relatively unknown is the fact that cervical fractures or fracture-dislocations to restrained front seat occupants occur where no head contact was evidenced by both medical records and car inspection. A review of the available literature on car crash injuries revealed more than 100 such cases. A review of the National Accident Severity Study (NASS) 80-88 file was also conducted, revealing more examples. Case capsule descriptions from the authors' files are also detailed along with examples of such injuries in infants and children in child restraints. However, cervical fractures or fracture dislocations are rare, as evidenced by the relatively few cases identified in the literature, in the author's files, and by an analysis of NASS 80-90 data that revealed a cervical spine injury frequency of only .4% at the AIS-3 level (Hueike, Morris, and Mackay 1992).

This paper documents field investigations of "air bag" crashes selected from a large group of air bag crashes in file at the University of Michigan Transportation Research Institute (UMTRI). A full range of crashes are presented with injury levels of AIS 1-2 to AIS 5-6. Most occupants sustained minor injuries. Those not wearing the lap-shoulder belt (3-point belt) had more minor injuries than the restrained. The occurrence of higher level injuries (AIS [ges]2) was found more often in the nonbelted.

We did a retrospective case control study to examine the relationship between the risk of dying for Michigan motor vehicle crash (MVC) drivers and the type of county (rural/nonrural) of crash occurrence, while adjusting for crash characteristics, age, sex, and the medical resources in the county of crash occurrence. The 1987 Michigan Accident Census was used to obtain data regarding all MVC driver nonsurvivors (733) and a random sample of all surviving drivers (2,483). County of crash occurrence was defined as rural or nonrural. The crash characteristics analyzed were vehicle deformity, seat belt use, and drivability of the vehicle from the scene. Age and sex of the driver were also analyzed. Medical resource characteristics for the county of crash occurrence were measured as the number of resources per square mile for each of the following: ambulances, emergency medical technicians (EMT), acute care hospital beds, and operating rooms, surgeons and emergency physicians. Also considered were the number and level of emergency rooms in the county of crash occurrence along with the maximum level of prehospital care available (basic life support versus advanced life support) in a county. Before adjusting, the relative risk (RR) for rural MVC drivers dying, compared to their nonrural counterparts, was 1.96. Adjustment for crash characteristics, age, and sex (using logistic regression) decreased the RR to 1.51. An attempt to add medical resource variables to the model resulted in high correlation with the rural/nonrural variable, as well as with each other. This multi-collinearity prevented us from providing a simple explanation of the role of medical resource variables as predictors of survival. We conclude that almost 50% of excess rural MVC mortality, as measured by the RR, can be accounted for by difference in crash characteristics and age. Delineation of the role of medical resources will require further investigation.

The aim of this research was to collect information and experimental data toward the development of a universally acceptable methodology for evaluating discomfort glare from vehicle headlamps. Three separate studies were performed: (a) an international survey of experts in headlighting and vision, soliciting opinions on desirable aspects of such a methodology; (b) a field evaluation of a proposed methodology at a speed of 50 km/hr (30 mph); and (c) a field evaluation at 100 km/hr (60 mph). The findings of this research suggest that the proposed methodology, which is easy to set up and implement, provides relatively reliable and valid measures of discomfort glare, and is time-efficient with respect to data collection.

A survey concerning international harmonization of accident reporting was distributed to 80 experts in accident reporting and analysis. Completed surveys were received from 50 persons in 13 countries, 74% of the respondents had more than 10 years of experience in the field of traffic safety. The main findings of this survey are: (1) 86% of the respondents think that an international computer file of disaggregated fatal-accident data would contribute to understanding of traffic safety, and 84% would use such a file. (2) An international non-fatal-accident file was considered to be of value in research on human factors and accident causation (60%), and in determining black spots in the road network (57%). (3) Police was the most frequently mentioned source of data for both the fatal and non-fatal international data files. Nevertheless, fewer than one-quarter of respondents considered police as the suitable exclusive source of either data. (4) The majority view was that the data for both types of files should come from more than one agency. (5) In the case of the fatal-accident file, 78% of the respondents considered it important that the data be cross-checked with the public health records. (6) The 10 most useful variables for a fatal-accident file were traffic unit type (e.g. car), accident type (e.g. angle), road class, driver age, date/time of day, age of person killed, number of killed persons, number of injured persons, drinking or drug use, and restraint usage of person killed. (7) The analogous 10 variables for a non-fatal-accident file were accident type, traffic unit type, driver age, date/time of day, road class, extent of injury, number of injured persons, age of involved persons, number of involved persons, and seat location.

Pigs and dogs have become common models of human thoraco-abdominal impact response. This paper summarizes a comparative analysis of the dog and pig to the live human accomplished through a series of necropsies performed on pigs and dogs. The results are summarized below. Emphasis is placed on specific aspects which are felt to be important for impact biomechanics. In particular, emphasis is placed upon the effect of tethering structures because of their potential in explaining mechanisms of injury for specific types of trauma such as aortic and certain liver injuries. Some aspects of tethering in the pig and dog are significantly different from that of the live human so care should be taken when using these animals in thoraco-abdominal biomechanics experiments.

This study evaluated the distributions of driver eye fixations when following other vehicles. The aim was to describe the areas of the forward field of view that are most frequently fixated. Such information is important for selecting optimal locations for automobile brake lights: Brake lights that are closer to eye fixations are likely to result in shorter driver reaction times than brake lights farther away from the fixations. A head-mounted, corneal-reflection device was used to monitor eye fixations. The data were collected during daylight hours in slow-moving urban traffic. A total of 3,600 eye fixations were analyzed for three different lead cars. The results indicate that, under the conditions of this study, the eye fixations tended to concentrate on the rear-window of the lead car and not in the neighborhood of the standard low-mounted brake lights. The results provide a possible behavioral explanation for the accident reductions found with high-mounted brake lights in previous field studies. Furthermore, high-mounted brake lights located at the edges of the vehicle might be even closer to eye fixations than a center-high-mounted brake light.

This study examined the future of personal transportation in megacities of the world., Of particular interest was the future role of personal vehicles. To span ranges of, geographical, political, and economic factors, the following 15 megacities were included, in the analysis: Chicago, New York, London, Moscow, Paris, Buenos Aires, Mexico City, Rio de Janeiro, São Paulo, Bangalore, Calcutta, Delhi, Mumbai, Hong Kong, and, Shanghai. The current and future values of the following factors were considered, population, wealth, level of motorization, public transportation, and modal split. Also, discussed were selected urban transportation plans and strategies., Based on the analysis, projections through 2025 were made for each megacity for, changes in ownership of personal vehicles; distance traveled by personal vehicle within, inner core, for commuting, and for leisure; and for number of road fatalities., The projections were based on treating the different transportation modes as, independent and exclusive options. However, there is growing implementation and use of, new mobility networks—integrated networks that provide a variety of connected and ITenhanced, transportation options door-to-door. Although such networks are expected to, reduce reliance on personal vehicles, the magnitude and nature of this effect remain to be, ascertained.

DTFH61-83-C-00123, The objectives of this project were to assess the capabilities that are needed in a road profilometer and develop a design tailored to minimize life costs of the system. This led to the development of a system based on the IBM PC microcomputer. With the exception of a signal conditioning unit, the system is constructed from commercial components. The software controls the measurement of road profile and rut depth, the viewing of the data, and daily checks of the hardware integrity. This document is the reference manual for the system--presently known as the PRORUT system. The manual in intended to document the software and hardware components of the system, and is of special interest to the technical staff responsible for maintenance, repair, or modification of the system when required. There are three companion reports prepared as part of the same project. One gives an overview of the project (FHWA/RD-87/042), another is the PRORUT User's manual (FHWA/RD-87/043), and the third describes the validation of the system along with other profilometers at a profilometer meeting (FHWA/RD-86/100).

FH-11-9577, This study has determined the influence of variations in truck size and weight constraints on the stability and control properties of heavy vehicles. The size and weight constraints of interest include axle load, gross vehicle weight, length, width, type of multiple-trailer combinations, and bridge formula allowances. Variations in location of the center of gravity of the payload were also considered as a separate subject. The influence of these parametric variations on stability and control behavior was explored by means of both full-scale vehicle tests and computer simulations. In Volume I, the findings of the study are presented in a manner which is intended to inform the non-technical reader and, specifically, the persons concerned with formulating policies and laws regarding truck size and weight. For each size and weight "issue" the stability and control problem areas are addressed and the influence of size and weight variations is quantified. The results are then reviewed in the light of their potential implications for traffic safety. Volumes II and III provide (a) background information concerning test procedures and analytical methods and (b) detailed data.

69A3551747105, This funding augmented maintenance and operations of the Ann Arbor Connected Environment. The Ann Arbor Connected Environment is one of the largest operational, real-world deployment of DSRC connected vehicles and infrastructure in the world. In 2017, it was expanded to encompass the entire City of Ann Arbor – 29 square miles. It has 70 infrastructure sites to include three curve speed warning sites, four pedestrian crosswalks, five freeway sites, one roundabout, two test sites, and fifty-five intersections that are instrumented. More than 2,200 cars, commercial trucks, and transit vehicles were equipped with global positioning systems and dedicated short-range communications. All devices pass industry certification testing and use production security. Additionally, the environment complies with all regulatory requirements such as FCC licensing. This project contributes to the continued operations and maintenance of the Ann Arbor Connected Environment, which is currently funded by Mcity. The Ann Arbor Connected Environment is used by many CCAT researchers and industry stakeholders. It enables research in all CCAT research thrusts for connected and automated transportation including Enabling Technology; Planning and Policy; Human Factors; Infrastructure Design and Management; Control and Operations; and Modeling and Implementation.

69A3551747105, Connected and automated vehicles (CAVs) represent a transformative technology that can revolutionize how people and goods move. The private sector is at the forefront of developing the technology, and many municipalities are attempting to prepare for a more connected and automated future. As such, both private and public sectors are in need of a skilled workforce with knowledge of CAVs. At the same time, as the CAV technology is not mature yet, academics are directing most of their attention to research on CAVs and their impact on the transportation system, overlooking needs for workforce development. The objective of this paper is to assess the needs for workforce development in CAVs, to identify potential obstacles that educators face in fulfilling those needs, and to propose ways to overcome the obstacles. Toward this end, a workshop was designed to bring together experts to identify the best ways to meet the demand for a workforce skilled in CAVs. As the field of CAVs can be diverse, a survey was distributed ahead of the workshop to identify the main themes around which the workshop was designed: (1) next generation infrastructure for CAVs, (2) human factors with CAVs, (3) modeling, simulation, and testing of CAVs, and (4) travel behavior in the context of CAVs. The identified themes do not comprehensively cover the educational needs in CAVs, but are rather poised to cover what were identified as the most prominent educational gaps in CAVs by the survey takers.

DTNH2216-P-00102, This project included tasks designed to identify psychological and communication theory to support traffic safety campaigns, identify campaigns currently using theory, obtain information from States about current traffic safety campaigns, and create resources for States and local jurisdictions to aid them in appropriately applying effective, theory-based campaign approaches to prevent distracted and alcohol-impaired driving.

DTFH61-82-C-00054, The problem of truck loss-of-control accidents on interchange ramps is examined from the viewpoint of the suitability of highway geometric design, given the peculiar stability and control limitations of heavy-duty trucks. Accident records were used to identify specific ramps which were overinvolved in jackknife, rollover, and run-off-road accidents. The ramp geometries were represented in a complex simulation of the dynamic behavior of representative tractor-semitrailer combinations. The calculated responses of heavy vehicles on each ramp were studied to illustrate how highway design features may have influenced the known accident experience at the site. Results show that various aspects of the AASHTO policy on geometric design result in a very slim margin of safety for the operation of heavy trucks on exit ramps. Problem features included side friction factors, superelevation transitions, compound curves, deceleration lanes, ramp downgrades, curbs on curved ramps, and wet surface friction on high-speed ramps. Potential countermeasures for the identified problems are suggested. Recommendations include a careful scoping of the prevalence of "problem ramps," nationally, initiation of efforts by State highway engineers to apply these findings to ramps having a known truck problem, and informing truck drivers of the situation involving slim safety margins.

DTRT5716C10014, This project included tasks designed to identify psychological and communication theory to support traffic safety campaigns, identify campaigns currently using theory, obtain information from States about current traffic safety campaigns, and create resources for States and local jurisdictions to aid them in appropriately applying effective, theory-based campaign approaches to prevent distracted and alcohol-impaired driving.

DTFH61-82-C-00054, The problem of truck loss of control accidents on interchange ramps is examined from the viewpoint of the suitability of highway geometric design, given the peculiar stability and control limitations of heavy duty trucks. Accident records were used to identify specific ramps which were over involved in jackknife, rollover, and run off road accidents. The ramp geometries were represented in a complex simulation of the dynamic behavior of representative tractor semitrailer combinations. The calculated responses of heavy vehicles on each ramp were studied to illustrate how highway design features may have influenced the known accident experience at the site. Results show that various aspects of the AASHTO policy on geometric design result in a very slim margin of safety for the operation of heavy trucks on exit ramps. Problem features included side friction factors, superelevation transitions, compound curves, deceleration lanes, ramp downgrades, curbs on curved ramps, and wet surface friction on high speed ramps. Potential countermeasures for the identified problems are suggested. Recommendations include a careful look at the prevalence of "problem ramps", nationally, initiation of efforts by State highway engineers to apply these findings to ramps having a known truck problem, and informing truck drivers of the situation involving slim safety margins.

DTFH61-91-R-00069, One of the identified truck accident types that occur on curved exit ramps at interchanges is truck rollover. A truck will overturn or rollover if the lateral acceleration imposed upon it as it travels around a curve of a certain radius and superelevation is greater than allowable given its loading condition. Also, there is a speed at which rollover will occur. This report deals with an automatic warning system to prevent truck rollover. Within the study, three different options were identified and evaluated for feasibility. Of the three, the option selected for further definition and cost-effectiveness analyses was an inroad detection/warning system. The system consists of two detection stations upstream of the curve with the combined ability to detect a truck speed, weight, and height threshold. The warning system is a combination of a static warning sign and a fiber-optic warning message sign, which would be activated if the controller determined that the truck would be operating at the rollover threshold speed or faster by the time it reached the point of curvature. This report provides the details of the design, its costs, and its cost-effectiveness. Also, design plans and specifications were prepared for three installations on the Capital Beltway in Maryland and Virginia.

DTFH61-85-C-00091, The purpose of this study is to examine changes to size and weight limits in order to determine their effects on the designs and configurations of heavy vehicles, the performance capabilities of the resulting vehicles, and the ensuing safety implications thereof. The summary report provides results and findings from an analytical investigation of the influences of size and weight limits on trucks. In an analytical sense, pavement loading rules and bridge formulas are the inputs to the analyses and vehicle performances are the outputs. Ultimately, the work shows the manner in which size and weight rules influence the safety-related performance of vehicles designed to increase productivity. By treating a number of projected size and weight scenarios, the study has developed a basis for generalizing to sets of principles that can be used in evaluating the possible safety consequences of changes in size and weight regulations.

"This document presents results from the light-vehicle and heavy-truck field operational tests performed as part of the Integrated Vehicle-Based Safety Systems (IVBSS) program. The findings are the result of analyses performed by the University of Michigan Transportation Research Institute to examine the effect of a prototype integrated crash warning system on driver behavior and driver acceptance. Both platforms included three integrated crash-warning subsystems: forward crash; lateral drift; and lane-change/merge crash warnings. The light-vehicle platform also included curve-speed warning. The integrated systems were introduced into two vehicle fleets: 16 light vehicles and 10 Class 8 tractors. The light vehicles were operated by 108 volunteer drivers for 6 weeks, and the heavy trucks were driven by 18 commercial-truck drivers for a 10-month period. Each vehicle was instrumented to capture detailed data on the driving environment, driver behavior, warning system activity, and vehicle kinematics. Data on driver acceptance was collected through post-drive surveys and debriefings. Key findings indicate that use of the integrated crash warning system resulted in improvements in lane-keeping, fewer lane departures, and increased turn-signal use. Both the passenger car and commercial drivers accepted the integrated crash warning system and benefited from improved awareness of vehicles around them. No negative behavioral-adaptation effects of using the integrated system were observed in either driver group."

DTFH61-89-C-00044, This report concerns in-car systems that may be used to present navigation, hazard warning, vehicle monitoring, traffic, and other information to drivers in cars of the future. It describes in detail measurements researchers have made to determine if those systems are safe and easy to use. Measures that appear most promising for safety and usability tests of driver information systems include the standard deviation of lane position, speed, speed variance, and the mean and frequency of driver eye fixations to displays and mirrors. In some cases, laboratory measures (errors, etc.) may also be useful. Also of interest are time-to-collision and time-to-line crossing, although hardware for readily measuring them in real time is not available. Of lesser utility are workload estimates (SWAT, TLX). Secondary task measures and physiological measures are very weak predictors of safety and usability. To assess usability, application-specific measures (e.g., the number of wrong turns made in using a navigation system) should be collected.

DTFH6116D00053L, Cruising vehicles—motorists circling or cruising for on-street parking that is free or priced below market equilibrium—can contribute to additional congestion, air pollution, time wasted, driver frustration, and a potential loss of economic competitiveness at destinations where parking is hard to find and where alternative access modes are limited. With increased sensitivity to the need for curb management, there is a need to better understand the prevalence of cruising for parking. This report documents a methodology and tool that can be used by municipalities and other interested parties to understand cruising for parking and the effects of policy interventions on parking search behaviors. It includes case analyses from four U.S. cities: Washington, DC; Atlanta, Georgia; Chicago, Illinois; and Seattle, Washington. The cases illustrate a range of applications, such as identifying cruising hot spots by time of day and location and assessing policy impacts. The highest rates of cruising were found in Seattle and Chicago where 7.3 and 6.8 percent of trips, respectively, showed some portion as cruising. Overall, the research team found that the level of cruising is consistent across the cities in this analysis, even when using different data sources. The report also documents lessons learned relating to data quality, tool implementation, and the analyses results.

69A3551747105, Autonomous vehicles (AVs) prospectively offer enhanced safety and mobility for travelers and increased efficiency of transportation system operations. AVs are likely to have significant impacts on the forms and functions of the built environment. In addition, the increasing urban air pollution, energy consumption, and climate change foster the need to promote adopting alternative fuel AVs such as all-electric AVs (EAVs) instead of gasoline-powered AVs (GAVs). This study seeks to comprehend the impacts of attitudinal factors and roadway designs on people’s intention to use AVs and buy EAVs and GAVs. Fourteen latent attitudinal factors related to people’s perceptions and attitudes towards AV and EV technologies, driving, the environment, and personal innovativeness were considered. Urban roadway designs for accommodating AVs were created to feature dedicated AV lanes equipped with wireless charging for EAVs and replacing roadside parking for AV pick-up/drop-off zones. Structural equation models were estimated using stated preference survey data collected from over 1,300 people across the United States. The model estimation results show the extent to which certain factors (the perceived advantages of AVs and EAVs, their potential to improve road safety, their compatibility with their users’ lifestyles and travel needs, and attitudes towards driving) prominently affect travelers intentions to use AVs and buy EAVs. The study results and insights can be used by transportation planners and policymakers to develop road network design guidelines and policies that target various attitudinal factors associated with AV adoption and promote EAVs over GAVs. Further, they can aid in preparing the built environment to facilitate AV adoption.

The Safety Pilot Model Deployment (SPMD) study was run in the Ann Arbor, MI area and involved over 2,000 vehicles. The study goal was to pilot a connected-vehicle system that included roadside units (RSUs) fixed to specific intersections and vehicle-based communication units. Data were collected from RSUs as well as vehicles. Each vehicle was equipped with one of four unique device packages which provide a series of data elements which communicate the vehicle's location and motion. The packages are referenced as the Integrated Safety Device (ISD); Aftermarket Safety Device (ASD); Retrofit Safety Device (RSD) and Vehicle Awareness Device (VAD). More than 75 percent of the total equipped vehicles used a VAD, which is the most primitive device. Vehicles with VAD can only transmit the data being generated and collected by their host vehicle; they are not able to receive messages transmitted from other vehicles. They mainly transmit "here I am" messages while increasing the likelihood of vehicle-to-Vehicle (V2V) and vehicle-to-infrastructure (V2I) interactions. More detailed vehicle-based data came from vehicles equipped with ISD, ASD, and RSD packages with the ability to collect, receive and transmit. Those vehicles had more advanced safety features and they also collected video data files. This dataset contains data from the onboard wireless safety units (WSUs). This file primarily consists of GPS-based data elements and those that are obtained from the vehicle’s Controller Area Network (CAN) Bus. Different brands of WSUs were used but all of the data were stored in one dataset. A series of data elements that present vehicle performance information and the state of a few of its components are also included.

69A3551747105, Leveraging recent advancements in distributed optimization and reinforcement learning, and the growing connectivity and computational capability of vehicles and infrastructure, we propose to advance real-time adaptive signal control via distributed control and optimization. This report consists of three parts. Part 1 develops distributed algorithms for solving a traffic signal timing optimization problem, which is formulated as a mixed-integer programming model. Specifically, the alternating direction method of multipliers (ADMM) is employed, and a two-stage stochastic cell transmission model (CTM) that considers the uncertainty of traffic demand and vehicle turning ratios is considered. Part 2 proposes a framework that utilizes reinforcement learning to optimize a max pressure controller considering the phase switching loss. The max pressure control is modified by introducing a switching curve, and the proposed control method is proved throughput-optimal in a store-and-forward network. Then the theoretical control policy is extended by using a distributed approximation and position-weighted pressure so that the policy-gradient reinforcement learning algorithms can be utilized to optimize the parameters in the policy network including the switching curve and the weigh curve. Part 3 applies reinforcement learning to traffic signal control in a multi-agent scheme, considering the data availability and implementability. The information extracted from traffic cameras is used to define the state of the agents; the action design is aligned with the NEMA dual-ring convention and bounded by a safety constraint, and the coordination is achieved by a shared reward structure among agents.

This report contains analyses of driving performance data from the Advanced Collision Avoidance System (ACAS) Field Operational Test (FOT), with data from nearly 100 drivers and over 100,000 miles of driving. The analyses compared normal and distracted situations and determined thresholds that distinguish between maneuvering and non-maneuvering situations. Four questions were addressed: 1. How are measures of driver input (steering wheel angle, etc.) and vehicle output (heading, speed, etc.) distributed as a function of 4 road types [(a) ramps, (b) interstates and freeways, (c) arterials and minor arterials, and (d) collectors and local roads]? 2. What is the effect of the number of tasks on measures of driver performance as a function of road type? (The distributions for 0 and 1 tasks were similar. For 2 tasks, the range was sometimes 50% less.) 3. How well do linear thresholds distinguish between maneuvering and non-maneuvering situations, and what should those values be? (It varies with the threshold; sometimes the odds were 10:1. Other times they were 1:1.) 4. How effectively do steering and throttle entropy predict distracted and normal driving? (Only steering entropy showed any differences.)

Manual. No date of publication., This web tool is an easy to use intuitive interface that uses Google maps to display and organize the results. This manual provides you with a basic understanding of how to navigate the tool. Additionally, we provide a case study of a possible use of the tool. For a more detailed description of the methodology underlying this tool, please see https://github.com/caocscar/pedbikeriskexposure/blob/master/draft.md

SPR-PL1(58)396-1, As part of the Long Term Pavement Performance (LTPP) Program, Arizona DOT constructed 16 SPS-1 test, sections on U.S. Route 93 near Kingman. The SPS-1 study was designed to study a variety of structural, sections in new asphalt concrete construction. Opened to traffic in 1993, the project was monitored at, regular intervals until it was rehabilitated in 2006. Surface distress, profile, and deflection data collected, throughout the life of the pavement were used to evaluate the performance of various flexible pavement, design features, layer configurations, and thickness. This report documents the analyses conducted as well, as practical findings and lessons learned that will be of interest to Arizona DOT.

This report is part of a series evaluating the data reported to the Motor Carrier Management Information System (MCMIS) Crash File undertaken by the Center for National Truck and Bus Statistics at the University of Michigan Transportation Research Institute. This report examines the factors that are associated with reporting rates for the state of Texas., Evaluating Texas data in the MCMIS Crash file presented unique problems. Gaps in the PAR data made difficult to identify vehicles that meet the MCMIS vehicle type criteria with confidence or to cleanly identify crashes meeting the severity threshold., Alternative methods were developed to evaluate reporting indirectly. The result of each method was consistent with the conclusion that Texas reporting is substantially complete. No evidence was found that would tend to show underreporting or overreporting. Missing data rates are low for most variables, and that data reported are consistent., However, it is emphasized that gaps in the Texas data make it impossible to directly measure crash reporting rates.

2010-0296, "Mobility, or the ability to get from place to place, is important for everyone. Mobility enables people to, conduct activities of daily life, stay socially connected with their world, participate in activities that make, life enjoyable, and increase their quality of life. In the United States, and indeed in Michigan, personal, mobility is frequently equated with being able to drive a personal automobile. However, because of agerelated, medical conditions and the medications used to treat them, as people age into older adulthood, they are more likely to experience declines in abilities needed for safe driving. Because of the preference, for the personal automobile, and the lack of acceptable mobility alternatives, one focus of efforts to, enhance safe mobility for older adults is to keep older adults driving for as long as they can safely do so., At the same time, society has a responsibility to help maintain mobility for those who are unable or, choose not to drive. As the population of older adults in Michigan continues to grow, it is becoming more, and more critical that the Michigan Department of Transportation (MDOT) understand the mobility needs, of older adults and incorporate these needs into transportation facility design and planning. This project, provided the background information needed to help MDOT identify where to concentrate resources to, maximize the safe mobility of Michigan’s aging population. The overall goal of the project was to help, maintain the safety and well-being of Michigan’s older adult residents by developing a set of low-cost, high-impact measures that could be implemented by MDOT. This goal was achieved through a literature, review, an analysis of demographic data, and statewide surveys of older adults and family, members/caregivers for Michigan older adults in order to gain a better understanding of the travel and, residency patterns, gaps in transportation services, and the transportation needs and wants of Michigan, older adult residents and the population of adults who provide care and/or transportation assistance to, Michigan older adults. The complete results of these research activities, a list of measures for, improving older adult mobility in Michigan, and an implementation plan are included in this report."

A nighttime field study was conducted to assess the effects of retroreflective material area, distribution, and, color on judgments of conspicuity. Participants, seated in a stationary vehicle, took part in a pairwise comparison, of the stimuli. The independent variables included retroreflective power, area and distribution of the, retroreflective material, color of the retroreflective material, participant age, and participant gender., The results indicate that color (white, fluorescent yellow-green, and fluorescent red-orange) was a significant, factor in the judgment of conspicuity, as might be predicted from the Helmholtz-Kohlrausch effect. In addition, color interacted with the distribution of material at the high level of retroreflective power. The area of the, retroreflective material was also significant., The present study, in agreement with a number of previous studies, indicates that color influences the, conspicuity of retroreflective stimuli, but that the results are not always in agreement with color correction factors, prescribed in ASTM E 1501. The discrepancy between empirically derived color correction factors seems to be, attributable to an interaction of the stimulus size (subtended angle) and color, which previous studies have not, extensively examined. To a lesser degree, the retroreflective power of a material also appears to influence, conspicuity., While the ASTM correction factors may be appropriate for intermediate subtended solid angles, particularly for, nonsaturated colors, smaller correction factors appear appropriate for markings subtending small angles, (approaching point sources), and larger factors for larger subtended angles of saturated stimuli.

DTMC75-06-H-00003, This report is part of a series evaluating the data reported to the Motor Carrier Management Information System (MCMIS) Crash File undertaken by the Center for National Truck and Bus Statistics at the University of Michigan Transportation Research Institute. Earlier studies have shown that reporting to the MCMIS Crash File was incomplete. This report examines the factors that are associated with reporting rates for the State of Florida., MCMIS Crash File records were matched to the Florida Crash file to determine the nature and extent of underreporting. Overall, it appears that Florida is reporting 28.0 percent of crash involvements that should be reported to the MCMIS Crash file. There is some disagreement in vehicle type as determined by VIN decoding and the entry recorded on the police accident report. The reporting rate for truck tractors is 46.7 percent, while the reporting rates for single unit trucks are 6.0, 16.2, and 24.2 percent for trucks with gross vehicle weight ratings in pounds of 10,000-19,5000; 19,501-26,000; and greater than 26,000, respectively. The reporting rate for buses is 5.3 percent., Fatal crashes are reported at about 86.0 percent, but injured/transported and towed/disabled crashes are reported at about 30.9 and 22.7 percent, respectively. The Highway Patrol has a reporting rate of 85.2 percent, while the reporting rate for police departments is 57.6 percent and for sheriff‘s offices is 60.6 percent., Missing data rates are low for most variables. There are some inconsistencies between vehicle configuration as coded in the Florida Crash file and the MCMIS file.

DRDA 04-4274, Subjects rated the workload of clips of forward road scenes (from the advanced collision avoidance system (ACAS) field operational test) in relation to 2 anchor clips of Level of Service (LOS) A and E (light and heavy traffic), and indicated if they would perform any of 3 tasks (dial a phone, manually tune a radio, enter a destination) in driving the scenes shown. After rating all of the clips, subjects rated a wider range of described situations (not shown in clips) and the relative contribution of road geometry, traffic, and other factors to workload. Using logistic regression, predictive equations for the refusal to engage in the 3 tasks were developed as a function of workload, driver age, and sex. Several equations were developed relating real-time driving statistics with workload, where workload was rated on a scale of 1 (minimum) to 10 (maximum). Some 87% of the rating variance was accounted for by the following expression: Mean Workload Rating=8.87-3.01(LogMeanRange)+ 0.48(MeanTrafficCount)+ 2.05(MeanLongitudinalAccleration), where range (to the lead vehicle) and traffic count were both determined by the adaptive cruise control radar. Other estimates were also generated from post-test ratings and adjustments, considering factors such as construction zones, lane drops, curves, and hills. From the results of this report alone, the workload estimates needed by a real-time workload manager could be developed using (1) the real time data, (2) look-up tables based on the clip ratings, (3) look-up tables based on the post-test data, or (4) some combination of those 3 sources.

This report is part of a series evaluating the data reported to the Motor Carrier Management Information System (MCMIS) Crash File undertaken by the Center for National Truck and Bus Statistics at the University of Michigan Transportation Research Institute. The earlier studies showed that reporting to the MCMIS Crash File was incomplete. This report examines the factors that are associated with reporting rates for the state of Mississippi., MCMIS Crash File records were matched to the Mississippi crash file to determine the nature and extent of underreporting. Overall, it appears that for 2008 Mississippi reported 38.0 percent of crash involvements that qualified for reporting to the MCMIS Crash file. About 3.0 percent of the reported cases did not meet the reporting criteria., Reporting rates were found to be related primarily to crash severity, the type of enforcement agency that covered the crash, and whether the reporting officer completed the Commercial Vehicle section of the Uniform Crash Report. Over 84 percent of fatal crashes were reported, compared with 36.4 percent of injury/transported crashes, and 35.8 percent of tow/disabled involvements. Reporting did not seem to vary significantly by truck size, but only 25 percent of “commercial” buses were reported, and less than 3 percent of school buses. Crashes covered by the State High Patrol were reported at the highest rate, though that was only 49.6 percent., Missing data rates are low for most variables. Overall, the crash report is designed to support full reporting. Most of the information necessary to identify reportable cases is available in the crash file, so a substantial improvement in the reporting rate can be achieved.

This report presents a time-series analysis of changes in road safety in the U.S. from, the public-health point of view. A 50-year period is examined, from 1958 to 2008. The, emphasis is on the changes by decades in fatalities per population across different age groups., The main findings are as follows. First, from 1958 to 2008, the overall fatality rate per, population decreased by 40%. Second, the decrease in the rate was age dependent (with the, largest decreases for the youngest and the oldest, and smallest decreases for the middle-aged)., Third, the overall fatality rate increased from 1958 to 1968, but it decreased for each of the four, following decades. Fourth, the changes in the rate for each decade were age dependent. Fifth, the patterns of these age-dependent changes varied across the decades., Examples of interventions that are likely to have age-dependent effects consistent with, the obtained differential age changes in the fatality rate are discussed. However, other, interventions are also likely to have relevant age-dependent effects on the fatality rate.

OR09102, Most countries around the globe are experiencing an aging of the population, due to decreased fertility, increased longevity, and the aging of the baby boomers (Global Action on Aging, 2010). Although global aging results, in part, from improved public health, medical care, and technology, it also creates new societal challenges. One challenge is how to maintain older adult safety and mobility in an aging society., Mobility enables people to engage in the activities needed to not only survive, but also to enjoy life. In most Western Nations and in the United States (US) in particular, mobility is closely linked with the ability to drive a personal automobile. However, as people age, they begin to experience age-related health conditions that can make it difficult to safely operate an automobile (Eby, Molnar, & Kartje, 2009). At the same time, if driving is limited or stopped completely, an individual’s need to get around still remains. Further, having to stop driving has been linked with a number of negative consequences including depression and a drop in overall well-being (e.g., Fonda, Wallace, & Herzog, 2001; Marottoli et al., 1997; Ragland, Satariano, & MacLeod, 2005). Thus, the challenge of maintaining safe mobility in an aging society has been characterized by four complementary and interdependent goals (Eby & Molnar, 2010): (1) to understand and better manage the effects of medical conditions and medications on skills needed for safe driving; (2) to develop and identify procedures and tools for determining fitness to drive; (3) to help those who are able to drive safely continue to do so; and (4) to identify and provide community mobility support to those who are no longer able or choose not to drive.

DTMC75-06-H-00003, This report is part of a series evaluating the data reported to the Motor Carrier Management Information System (MCMIS) Crash File undertaken by the Center for National Truck and Bus Statistics at the University of Michigan Transportation Research Institute. The earlier studies showed that reporting to the MCMIS Crash File was incomplete. This report examines the factors that are associated with reporting rates for the state of Minnesota., MCMIS Crash File records were matched to the Minnesota Crash file to determine the nature and extent of underreporting. Overall, it appears that Minnesota is reporting 79.9 percent of crash involvements that should be reported to the MCMIS Crash file. Reportable cases could be identified in the Minnesota data reasonably well using the coded data, with some qualification for the towed/disabled crash severity., Reporting rates were related to crash severity, with fatal or injury/transported involvements most likely to be reported, and tow/disabled crashes less likely. Reporting rates also varied by the type of vehicle, with small buses (8-15 passenger) less likely to be reported than trucks or large buses; by state of registration, with in-state vehicles less likely to be reported than out-of-state; and by the type of investigation agency (state police, county, or city police)., Missing data rates are low for most variables reported to the crash file. Some inconsistencies between data reported to the MCMIS file and recorded in the Minnesota data were also noted.

DTNH22-10-C-00185, work unit no. 065442, "NHTSA selected the vehicle footprint (the measure of a vehicle’s wheelbase multiplied by its average track width) as the attribute upon which to base the CAFE standards for model year 2012-2016 passenger cars and light trucks. These standards are likely to result in weight reductions in new light duty vehicles. As part of its regulatory analysis, the government would like to estimate the effect of the new CAFE standards on safety in terms of crash injuries and fatalities. A number of fairly comprehensive statistical papers have been published analyzing associations between fatality/injury rates and vehicle weight, track width, and wheelbase. Many of the papers arrive at conclusions that are inconsistent., This report is a review of papers analyzing associations between crash/fatality outcome and vehicle weight and size. The various studies are based on different data sources, model assumptions, and methodologies. The authors of these studies represent a mix of those in government, research institutes, and academia, and have a broad range of professional backgrounds and philosophies. The goal of this report is to provide an independent review of the papers and to critically assess the methods and conclusions presented. The review is independent in the sense that it was conducted by a third party without any interest in the reported outcome. This review focuses on issues such as multicollinearity, data sources, the use of logistic regression, and induced exposure methods. Comments and suggestions are also made with regard to methods used in the various papers."