Road Safety Audit for the Intersection of US 59 and IA 9 in Osceola County, Iowa Final Report, March 2012

The Iowa Department of Transportation (DOT) requested a road safety audit (RSA) of the US 59/IA 9 intersection in northwestern Iowa, just south of the Minnesota border, to assess intersection environmental issues and crash history and recommend appropriate mitigation to address the identified safety issues at the intersection. Although the number of crashes at the location has not been significantly higher than the statewide average for similar intersections, the severity of these crashes has been of concern. This RSA was unique in that it included intersection video observation and recorded traffic conflict data analysis, along with the daylight and nighttime field reviews. This report outlines the findings and recommendations of the RSA team for addressing the safety concerns at this intersection

Synthesis of Best Practice for Increasing Protection and Visibility of Highway Maintenance Vehicles, CTRE Final Report Iowa DOT Project TR-475, August 2002

The purpose of this research project is to study current practices in enhancing visibility and protection of highway maintenance vehicles involved in moving operations such as snow removal and shoulder operations, crack sealing, and pothole patching. The results will enable the maintenance staff to adequately assess the applicability and impact of each strategy to their use and budget. The report’s literature review chapter examines the use of maintenance vehicle warning lights, retroreflective tapes, shadow vehicles and truck-mounted attenuators, and advanced vehicle control systems, as well as other practices to improve visibility for both snowplow operators and vehicles. The chapter concludes that the Manual on Uniform Traffic Control Devices does not specify what color or kind of warning lights to use. Thus, a wide variety of lights are being used on maintenance vehicles. The study of the relevant literatures also suggests that there are no clear guidelines for moving work zones at this time. Two types of surveys were conducted to determine current practices to improve visibility and safety in moving work zones across the country and in the state of Iowa. In the first survey of state departments of transportation, most indicated using amber warning lights on their maintenance vehicles. Almost all the responding states indicated using some form of reflective material on their vehicles to make them more visible. Most participating states indicated that the color of their vehicles is orange. Most states indicated using more warning lights on snow removal vehicles than their other maintenance vehicles. All responding state agencies indicated using shadow vehicles and/or truck-mounted attenuators during their moving operations. In the second survey of Iowa counties, most indicated using very similar traffic control and warning devices during their granular road maintenance and snow removal operations. Mounting warning signs and rotating or strobe lights on the rear of maintenance vehicles is common for Iowa counties. The most common warning devices used during the counties’ snow removal operations are reflective tapes, warning flags, strobe lights, and auxiliary headlamps

A Vision-Based Driver Nighttime Assistance and Surveillance System Based on Intelligent Image Sensing Techniques and a Heterogamous Dual-Core Embedded System Architecture

This study proposes a vision-based intelligent nighttime driver assistance and surveillance system (VIDASS system) implemented by a set of embedded software components and modules, and integrates these modules to accomplish a component-based system framework on an embedded heterogamous dual-core platform. Therefore, this study develops and implements computer vision and sensing techniques of nighttime vehicle detection, collision warning determination, and traffic event recording. The proposed system processes the road-scene frames in front of the host car captured from CCD sensors mounted on the host vehicle. These vision-based sensing and processing technologies are integrated and implemented on an ARM-DSP heterogamous dual-core embedded platform. Peripheral devices, including image grabbing devices, communication modules, and other in-vehicle control devices, are also integrated to form an in-vehicle-embedded vision-based nighttime driver assistance and surveillance system

Dark Model Adaptation: Semantic Image Segmentation from Daytime to Nighttime

This work addresses the problem of semantic image segmentation of nighttime scenes. Although considerable progress has been made in semantic image segmentation, it is mainly related to daytime scenarios. This paper proposes a novel method to progressive adapt the semantic models trained on daytime scenes, along with large-scale annotations therein, to nighttime scenes via the bridge of twilight time -- the time between dawn and sunrise, or between sunset and dusk. The goal of the method is to alleviate the cost of human annotation for nighttime images by transferring knowledge from standard daytime conditions. In addition to the method, a new dataset of road scenes is compiled; it consists of 35,000 images ranging from daytime to twilight time and to nighttime. Also, a subset of the nighttime images are densely annotated for method evaluation. Our experiments show that our method is effective for model adaptation from daytime scenes to nighttime scenes, without using extra human annotation.Comment: Accepted to International Conference on Intelligent Transportation Systems (ITSC 2018

Evaluation of Machine Vision Collected Pavement Marking Quality Data for Use in Transportation Asset Management

Transportation departments are tasked with managing numerous assets that are part of the roadway infrastructure. One of the most challenging pieces of transportation asset management is pavement markings. There are several characteristics of pavement markings that make them difficult to incorporate into an asset management system including the volume of markings on the roadway and the lack of easy, standardized data collection methods. Machine vision technology has potential applications in transportation asset management and could alleviate some of the problems currently faced in managing pavement markings as an asset. Advanced driver assistance systems (ADAS) incorporating machine vision cameras have the ability to assign quality ratings to individual pavement markings, and vehicles equipped with machine vision have the capability to collect large amounts of data without direct input from the vehicle operator. The large amount of data collected by ADAS machine vision cameras is readily stored and easily processable for asset management decision-making. In order for the machine vision data to be useful in pavement marking asset management, the reliability of the quality scores and their relationship to established pavement marking evaluation characteristics needed to be investigated. The purpose of this research was to explore the repeatability of the quality scores assigned by the machine vision camera under different collection conditions. Along with determining the correlation between the machine vision quality scores and the defined pavement marking characteristics retroreflectivity, luminance, and contrast. The results of the analysis were that the ADAS machine vision quality scores were determined to be mostly reliable under each individual condition but not across the different collection conditions. An acceptable relationship between the current pavement marking evaluation characteristics and the machine vision quality scores was not able to be conclusively established using several different regression approaches as a result of the correlation analysis. From the analysis that was done as a part of this research, it is recommended that further data collection efforts be conducted under various conditions in order to expand on both the repeatability and correlation analysis that was performed

Investigation of smart work zone technologies using mixed simulator and field studies

Safety is the top concern in transportation, especially in work zones, as work zones deviate from regular driving environment and driver behavior is very different. In order to protect workers and create a safer work zone environment, new technologies are proposed by agencies and deployed to work zones, however, some are without scientific study before deployment. Therefore, quantitative studies need to be conducted to show the effectiveness of technologies. Driving simulator is a safe and cost-effective way to test effectiveness of new designs and compare different configurations. Field study is another scientific way of testing, as it provides absolute validity, while simulator study provides relative validity. The synergy of field and simulator studies construct a precise experiment as field study calibrates simulator design and validates simulator results. Two main projects, Evaluation of Automated Flagger Assistance Devices (AFADs), and Evaluation of Green Lights on Truck-Mounted Attenuator (TMA), are discussed in this dissertation to illustrate the investigation of smart work zone technologies using mixed simulator and field studies, along with one simulator project investigating interaction between human driven car and autonomous truck platoon in work zones. Both field and simulator studies indicated that AFADs improved stationary work zone safety by enhancing visibility, isolating workers from immediate traffic, and conveying clear guidance message to traffic. The results of green light on TMAs implied an inverse relationship between visibility/awareness of work zone and arrow board recognition/easy on eyes, but did not show if any of the light configurations is superior. Results anticipated for autonomous truck platoon in work zones are drivers behave more uniformly after being educated about the meaning of signage displayed on the back of truck, and performance measured with signage would be more preferable than those without signage. Applications of statistics are extension of studies, including experimental design, survey design, and data analysis. Data obtained from AFAD and Green Light projects were utilized to illustrate the methodologies of data analysis and model building, which incorporated simulator data, biofeedback and survey response to interpret the relationship among driver perspective and mental status, and driving behavior. From the studies conducted, it could be concluded that mixed simulator and field study is a good fit for smart work zone technologies investigation. Simulators provide a safe environment, flexibility and cost-effectiveness, while field studies calibrate and validate simulator setup and its results. The collaboration of two forms of study generates legitimate and convincing results for investigations. Applying statistical methodologies into transportation simulator and field studies is a good way to make experiment and survey design more rational, and the statistical methods are applicable for further data analysis.Includes bibliographical reference

Evaluating the use of steady burn warning lights on drums for workzone safety

Abstract EVALUATING THE USE OF STEADY BURN WARNING LIGHTS ON DRUMS FOR WORK ZONE SAFETY by PRASAD LAKSHMI VARA NANNAPANENI May 2011 Advisor: Dr. Timothy Gates Major: Civil Engineering Degree: Doctor of Philosophy Roadway maintenance and repair has become increasingly commonplace in the United States over the past several decades as our roadway infrastructure has continued to age and deteriorate. Maintenance and repair work on an existing roadway often presents the challenge of maintaining traffic on the existing roadway while work is being performed, thereby necessitating the use of what is commonly referred to as a roadway work zone . One of the most important components of traffic control in a work zone is delineation of the edge of the traveled way, which assists drivers with tasks such as: lane selection; lateral positioning within a lane; and speed control. Delineation of the edge of the traveled way is commonly provided by a series of portable devices, such as drums, cones, vertical panels, or barricades. The type and duration of the work being performed often requires that these channelizing devices remain in place at all times. Maintaining traffic through nighttime work zones poses increased risks for drivers and roadway workers due to the lack of ambient light. To help overcome nighttime visibility issues, the 2009 Manual on Uniform Traffic Control Devices (MUTCD) requires work zone traffic control devices to be retroreflective or internally illuminated. To help supplement retroreflectivity, Section 6F.81 of the 2009 MUTCD allows for the use of auxiliary steady burn warning lights (SBWL) on work zone channelizing devices. Until recently, plastic drums with steady burn warning lights had been the primary channelizing device utilized in work zones throughout the State of Michigan for several years. However, the use of sheeting materials with improved retroreflectivity, including high intensity and microprismatic (i.e., prismatic) materials, has prompted investigation into the value and effectiveness provided by the steady burn warning lights. Furthermore, although previous research has explored the effectiveness of steady burn warning lights on drums both in Michigan and elsewhere, these efforts included a relatively limited number of work zone sites and/or focused on controlled human factors experiments. As a result, research was undertaken to explore the impacts associated with the use of steady burn warning lights on channelizing drums considering a variety of work zone scenarios utilized in Michigan. The primary goal of this research was to evaluate the safety impacts associated with the use of steady burn warning lights on drums in roadway work zones in Michigan. The following research objectives were addressed in this study: 1. Determine the state-of-the-art of work zone channelization through a comprehensive literature review. 2. Determine the state-of-the-practice regarding the use of steady burn warning lights by roadway agencies throughout the United States. 3. Assess the crash experiences of states with respect to the work zone steady burn warning light policy or practice. 4. Evaluate the impacts that steady burn warning lights on channelizing drums have on work zone crash occurrence in Michigan. 5. Evaluate the driver behavioral impacts associated with the use of steady burn warning lights on channelizing drums in Michigan work zones. 6. Determine the degree by which steady burn warning lights affect the overall brightness of work zone drums in Michigan. 7. Assess the overall impacts of steady burn warning lights on work zone safety. A comprehensive research methodology was developed to address these objectives. The initial tasks involved a comprehensive review of the current state-of-the-art and a state DOT survey related to the use of drums or other channelizing devices in roadway work zones, both with and without the presence of steady burn warning lights. The next tasks involved a comparison of work zone crash trends, both among states with varying policies on the use of steady burn warning lights, as well as a detailed investigation of crash data for work zones within the State of Michigan. To further supplement the crash data, a series of field studies were performed at 36 Michigan work zones to provide a more in-depth evaluation of differences in driver behavior and performance with respect to the use of steady burn warning lights. In addition to these field studies, a series of luminance tests were also conducted to assess the relative brightness levels provided by drums with and without warning lights. The luminance tests were performed both in the field and in a controlled environment to gauge the impacts of steady burn warning lights on drum visibility. Established sampling procedures were utilized to determine the target sample sizes necessary to assess statistical inference on the measures of effectiveness (MOEs). The data were collected for each study component under a variety of representative field conditions, which included different types of roadways, work zone configuration, levels of ambient lighting, roadway geometry, and other factors. Each of the MOEs were analyzed using appropriate statistical techniques to determine the impacts of steady burn warning lights and the impacts of other factors. The results showed that the presence of steady burn warning lights on work zone channelizing drums increased the occurrence of risky driver behavior, as evidenced by a higher proportion of drivers traveling too close to the drums, more frequent steering reversals, and higher vehicular speeds. These findings were further substantiated by the observance of a greater proportion of damaged drums at work zone locations with steady burn warning lights. Steady burn warning lights were not found to provide substantial increases to the luminance of the drums either in the field or in a controlled environment. It was determined that the use of microprismatic sheeting materials provide considerably greater luminance increases for the drums compared to the addition of a steady burn warning light to the drum. The state DOT survey revealed that only approximately one-third of the 42 responding state agencies utilize steady burn warning lights on channelizing devices in work zones and only one-tenth of the responding agencies utilize them on a frequent basis. The majority of agencies that use steady burn warning lights do so on an infrequent basis, typically for specific types of applications, such as at spot hazards, tapers, lane shifts, and crossovers. The investigation of nationwide work zone crash statistics revealed only slight differences between the rates of work zone crashes for the various steady burn warning light usage practices. The states that frequently use lights on drums exhibited a slightly higher aggregate work zone crash rate, while the states that infrequently use lights on drums had the lowest aggregate crash rate. No discernable differences were observed between any of the three groups of states when examining work zone crashes as a proportion of total crashes. A detailed review of Michigan work zone crash statistics revealed that a higher proportion of work zone crashes tended to occur during nighttime conditions at locations with steady burn warning lights compared to locations without steady burn warning lights. Deeper investigation showed that among those crashes occurring in the presence of drums, the proportion of the crashes that may have been affected by the drums was indistinguishable between the two samples. Based on a synthesis of all results, steady burn warning lights demonstrate no substantive value to nighttime brightness, driver behavior, or crash prevention when used on channelizing drums in work zones. Thus, it was concluded that steady burn warning lights demonstrate no additional safety benefit when used on channelizing drums in work zones. Furthermore, steady burn warning lights may actually contribute to a greater crash risk due to the increase in risky driver behavior that was observed when steady burn warning lights were present. Drums with high intensity sheeting that is in good condition will provide adequate nighttime brightness for work zone channelization regardless of whether a steady burn warning light is attached or not. Therefore, it is recommended that the use of steady burn warning lights on work zone drums be discontinued. If additional nighttime brightness of the channelizing devices is desired, the use of microprismatic sheeting on the drums provides far greater increases in brightness than the addition of a steady burn warning light

Beer Taxes, the Legal Drinking Age, and Youth Motor Vehicle Fatalities

Based on a time series of state cross sections for the period from 1975 through 1981, we find that motor vehicle accident mortality rates of youths ages 15 through 17, 18 through 20, and 21 through 24 are negatively related to the real beer excise tax. We also find that the death rate of 18 through 20 year olds is inversely related to the minimum legal age for the purchase of beer. Simulations suggest that the lives of 1,022 youths between the ages of 18 and 20 would have been saved in a typical year during the sample period if the Federal excise tax rate on beer, which has been fixed in nominal terms since 1951, had been indexed to the rate of inflation since 1951. This represents a 15 percent decline in the number of lives lost in fatal crashes. The simulations also suggest that the lives of 555 youths per year would have been saved if the drinking age had been 21 in all states of the U.S. These figures indicate that, if reductions in youth motor vehicle accident deaths are desired, both a uniform drinking age of 21 and an increase in the Federal excise tax rate on beerare effective policies to accomplish this goal. They also indicate that the tax policy may be more potent than the drinking age policy.

A Simple and Effective Display for Night Vision Systems

The next generation of automotive night vision systems will likely continue to display to the driver enhanced images of the forward driving scene. In some displays there may also be highlighting of pedestrians and animals, which has been argued to be the primary safety goal of night vision systems. We present here the method that was used to design a conceptual display for night vision systems. Although the primary focus of the method is on safety analysis, consideration is given to driver performance with the system, and exposure to alerts. It also addresses user acceptance and annoyance, distraction, and expected behavior adaptation. The resulting driver interface is a simple and potentially effective display for night vision systems. It consists of a pedestrian icon that indicates when there are pedestrians near the future path of the vehicle. An initial prototype of this night-vision DVI was tested on the road and showed promising results despite its simplicity. It improved pedestrian detection distance from 34 to 44 m and decreased the overall ratio of missed pedestrians from 13% to 5%, correspondingly. The improvement may be attributable to the icon alerting the driver to the presence of a pedestrian. In this experiment, the drivers were probably more alert to the possible presence of pedestrians than drivers in the real world, suggesting that the effect of the icon might be even larger in actual use