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Autonomous Vehicle (AV) technology is quickly becoming a reality on US roads. Testing on public roads is currently undergoing, with many AV makers located and testing in Silicon Valley, California. The California Department of Motor Vehicles (CA DMV) currently mandates that any vehicle tested on California public roads be retrofitted to account for a back-up human driver, and that data related to disengagements of the AV technology be publicly available. Disengagements data is analyzed in this work, given the safety-critical role of AV disengagements, which require the control of the vehicle to be handed back to the human driver in a safe and timely manner. This study provides a comprehensive overview of the fragmented data obtained from AV manufacturers testing on California public roads from 2014 to 2017. Trends of disengagement reporting, associated frequencies, average mileage driven before failure, and an analysis of triggers and contributory factors are here presented. The analysis of the disengagements data also highlights several shortcomings of the current regulations. The results presented thus constitute an important starting point for improvements on the current drafts of the testing and deployment regulations for autonomous vehicles on public roads. [ABSTRACT FROM AUTHOR]

This article studies a capacitated fixed-charge multiperiod location–transportation problem in which, while the location and capacity of each facility must be determined immediately, the determination of the final production and distribution of products can be delayed until actual orders are received in each period. In contexts where little is known about future demand, robust optimization, namely using a budgeted uncertainty set, becomes a natural method for identifying meaningful decisions. Unfortunately, it is well known that these types of multiperiod robust decision problems are computationally intractable. To overcome this difficulty, we propose a set of tractable conservative approximations for the problem that each exploit to a different extent the idea of reducing the flexibility of the delayed decisions. While all of these approximation models outperform previous approximation models that have been proposed for this problem, each also has the potential to reach a different level of compromise between efficiency of resolution and quality of the solution. A row generation algorithm is also presented to address problem instances of realistic size. We also demonstrate that full flexibility is often unnecessary to reach nearly, or even exact, optimal robust locations and capacities for the facilities. Finally, we illustrate our findings with an extensive numerical study where we evaluate the effect of the amount of uncertainty on the performance and structure of each approximate solution that can be obtain d. [ABSTRACT FROM AUTHOR]

We study an emergency response network design problem that integrates relief (supply) and evacuation (demand) sides under disaster location and intensity uncertainties which, in turn, dictate uncertainty in terms of the location and amount of demand. Representing these uncertainties by discrete scenarios, we present a stochastic programming framework in which two second stage objectives, the average and worst case costs, are combined. In our model, we minimize, over all of the scenarios, the fixed costs of opening supply centers and shelters, and the weighted sum of average and worst case flow costs. Thus, the model gives the decision maker the flexibility to put relative emphasis on the worst case and average flow cost minimization and explore outcomes in terms of total costs and network configurations. To solve large scale instances with varying relative weights, we devise alternative Benders Decomposition approaches. We implement these by using an advanced callback feature of the solver while simultaneously incorporating several performance-enhancing steps that help to improve runtimes significantly. We conduct a detailed computational study to highlight the efficiency of our proposed solution methodology. Furthermore, we apply our approach in a realistic case study based on Geographical Information Systems data on coastal Texas and present interesting insights about the problem and the resulting network structures for varying weights assigned to objectives. [ABSTRACT FROM AUTHOR]

The article highlights the role of traffic enforcement, analyzes its efficacy to deter dangerous driving, and suggests a new framework for traffic enforcement suited to the goals of Vision Zero. It suggests that primary goal of Vision Zero-related traffic enforcement must be to create long-lasting deterrence of dangerous driving behavior.

The article examine the use of dynamic lane grouping (DLG) for lane adjustment assignment based traffic management. Topics discussed include benefits resulting from DLG such as improved traffic operational efficiency at signalized intersections, signal timing optimization, and use of safe turning geometry for DLG treatment.

This paper presents an investigation into the current U.S. practice regarding the use of channelized right-turn lanes at signalized intersections, the type of traffic control used, and the safety experience of highway agencies. The study involved a literature review and a practice survey, which was distributed to all state and selected local agencies in the United States. The literature review revealed the overall lack of knowledge about the operational and safety aspects of channelized right-turn lanes explaining, to a large extent, the lack of guidance in practice. Survey results suggest a heavy reliance on engineering judgment by highway agencies in the use of channelized right-turn lanes and the selection of traffic control. Further, results confirmed a general perception in practice about the safety benefits of signal control at channelized right-turn lanes, despite the fact that such benefits were not supported by studies or statistics. The study emphasized the need for further research on the operational and safety aspects of this right-turn treatment at intersections. [ABSTRACT FROM AUTHOR]

The article presents an analysis of local regulations of secondary culprits using automated traffic enforcement schemes in the U.S. It discusses various aspects of traffic regulation including bad turn, speeding, and red light violations. It mentions federal court decisions that sustain these automated schemes challenged on constitutional grounds and preemption. It explores the possible governmental regulations in and out of traffic settings in the presence or absence of automated enforcement.

Minimum sign retroreflectivity standards issued by the Federal Highway Administration (FHWA) on January 29, 2008, have focused the attention of administrators and sign managers on improving the nighttime performance of traffic signs. To predict when a sign will need replacement, an agency will need to know when the retroreflectivity of signs with similar characteristics deteriorate to the minimum level established by the FHWA. Currently in the literature, there is limited information about the long-term deterioration behavior of ASTM Type III and IX signs. One way of achieving a better understanding of long-term sign deterioration is to establish an experimental sign retroreflectivity measurement facility (ESRMF). An ESRMF is an arrangement of signs in a controlled area that have their retroreflectivity measured at regular intervals to determine how it deteriorates as a function of time. This article shows how such a facility should look and why. A template is presented that can be used by agencies nationwide for collecting critical sign data to inform policy decisions. [ABSTRACT FROM AUTHOR]

MANY COUNTRIES ARE IMPLEMENTING POLICIES AND PROGRAMS TO IMPROVE THE SAFETY AND MOBILITY OF AN AGING POPULATION. A SCAN MISSION TO JAPAN AND AUSTRALIA LED TO A NUMBER OF FINDINGS AND RECOMMENDATIONS FOR THE UNITED STATES. ALL LEVELS OF GOVERNMENT MUST COOPERATE TO ENSURE THAT THE MOBILITY NEEDS OF OLDER ROAD USERS ARE SAFELY MET [ABSTRACT FROM AUTHOR]

The article focuses on various articles published in Journal of the Transportation Research Forum, related to transportation safety. In the article "New Speed Limits on Kansas Highways: Impact on Crashes and Fatalities," by Yacoub Najjar, Eugene Russell, Robert Stokes, and Ghassan Abu-Lebdeh examine the impact of recent changes in speed limits on Kansas highways. The authors note that the National Maximum Speed Limit of 55 mph was eliminated in November 1995, thus returning the authority of establishing speed limits to the states. By the end of 1996 a total of 32 states had raised speed limits on their highways. In Kansas, speed limits of most rural, separated, multilane highways were raised to 70 mph, while on most urban interstate and two-lane rural highways the limit was increased to 65 mph. The main objective of the paper is to determine whether statistically significant changes have occurred in accident related indices such as crash, fatal crash, and fatality rates after the Kansas speed limits were increased. In the article "Seat Belt Use Compliance in Kansas," by Deogratias Eustace and Teresa Bartel examine trends in Kansas seat belt use.

The article offers information on the development of the second edition of the Federal Highway Administration's (FHWA) "Roundabouts: An Informal Guide." It states that the said publication, which follows the first version in 2000, are split into separate chapters containing updates on trade-offs in planning and design decisions, safety analysis procedure, and guidance on traffic control device application. It notes that the project is to be launched in 2010.

The article underscores a roadmap of highway safety legislation. It states that a report from US pressure group Advocate for Highway and Auto Safety underlines gaps in a list of 15 important and lifesaving highway safety laws. Relative to this, this necessitated that governors and state legislators in the United States should act correspondingly on this issue. It is also posed that motor vehicle crashes caused 42,000 and over 2.5 million injuries in 2006.