1,722,088 research outputs found
Low-cost road marking measures for increasing safety in horizontal curves: A driving simulator study
No full textStatistics show that horizontal curves, especially those of radii less than 200 m, present an increased road ac-cident risk mainly due to inappropriate speed and failure to maintain proper lateral position. This simulator study aims to analyse how two low-cost road marking measures (red median and horizontal warning signs), alone or combined with a vertical warning sign, affect driver behaviour (driving speed, lateral movement, ac-celeration/deceleration) before and throughout dangerous horizontal curves on a two-way rural road. With GIS-supported mapping of traffic accidents, we identified the most dangerous curves on the main rural road in Croatia and replicated them on the driving simulator. Based on the driving runs of 43 participants, the study concluded that both measures, used either alone or combined with a vertical warning sign, significantly reduced the speed compared to the control condition (vertical warning sign alone). Additionally, the use of a red median prompted the lateral movement of the vehicle closer to the edge line. The paper also defines the potential use of the measures for dealing with specific types of curve-related accidents.This research was a part of the project entitled: "Understanding the impact of traffic signalling on the driver behaviour" and funded by a Unity Through Knowledge Fund "Gaining Experience Grant".Babic, D (corresponding author), Univ Zagreb, Fac Transport & Traff Sci, Zagreb, Croatia.
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Safety implications of higher levels of automated vehicles: a scoping review
No full textAutomated vehicles (AVs) promise to improve road safety, reduce traffic congestion and emissions, and enhance mobility. However, evidence regarding their safety benefits has not been systematically investigated and documented. In this study, we utilise a scoping review approach to investigate and synthesise the existing literature on higher levels of AVs’ safety implications. This aids future relevant studies by identifying the research gaps and reporting the methodological approaches used. The review focused not only on peer-reviewed articles but also on grey literature to provide a comprehensive overview of the current research state. In total, 5724 articles were identified, and 4167 records were screened after duplicates and dual publications removal, from which 27 were found eligible for review. Ultimately, 24 studies met all the inclusion criteria and were considered for the review. The reported evidence was focused on changes in road safety levels after the deployment of AVs in transport networks. The data was extracted and charted by one reviewer using tables to create a descriptive summary of the results and address the scoping review's questions and objectives. In general, the findings suggest that AVs hold the potential to improve the overall safety on roads, although the existing evidence is not mainly based on real data but assumptions regarding vehicles’ capabilities and behaviour. The limited number of studies and the fact that all of them were published or conducted after 2014 indicate that the research on AVs’ safety impacts is just emerging.Accepted Author ManuscriptTransport and Plannin
Aanbevelingen voor richtlijnenkader Vrij Programmeerbare Verlichte Publiciteitsinrichtingen (VPVP's)
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Replication of Daily and Monthly Freeway Demand Variations for Travel Time Reliability Procedures
No full textThe sixth edition of theHighway Capacity Manual(HCM) incorporates a travel time reliability assessment procedure for freeways and urban streets. Several demand adjustment factors, referred to by demand multipliers, are used to capture traffic demand variation across different days and months. These factors are currently produced by referencing the average daily traffic volume of each day-month combination to a base daily volume. However, practitioners usually perform traffic analyses during specific times of the day, for example, peak periods, off-peak periods, or even peak hours, demand multipliers may therefore replicate demand variation more accurately if they are based on traffic volumes concurred in time intervals narrower than a day. This paper investigates six criteria or periods to derive demand multipliers: full-day, pre AM-peak, AM peak-period, midday, PM peak-period, and post PM-peak. The study explores how these periods affect the scale of demand multipliers and the travel time reliability assessment. It was found that the main statistics of demand multipliers, that is, the mean, range, and standard deviation, greatly differ across the different multiplying periods. If analyzing peak periods on oversaturated corridors, the adoption of daily-volume multipliers was found to significantly overestimate the mean travel time index and planning time index during both the AM and PM peak periods, the accuracy of the travel time reliability estimation was considerably influenced. The study concludes with major findings and recommendations for possible enhancements to the HCM travel time reliability procedure.Dehman, A (corresponding author), Hasselt Univ, Transportat Res Inst IMOB, Diepenbeek, Belgium.
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“Everything somewhere” or “something everywhere”: Examining the implications of automated vehicles’ deployment strategies
No full text“Everything somewhere” or “something everywhere” is the classic dilemma concerning the development and implementation of the future generation of vehicles, i.e., automated vehicles (AVs). Both strategies include diverse policy options that could significantly impact road networks’ planning, design, operation, and utilization. Until now, no significant research has been conducted concerning their implications. In this paper, we aim to examine how ready the current physical infrastructure is by identifying the requirements of each strategy and then applying them in a com-mon type of intersection. The study’s findings demonstrate that AVs’ performance can be affected by policy implementation decisions and adds further weight to the argument of AVs separation or no-separation from no-AVs traffic. Furthermore, the insignificant improvements in traffic performance imply the low readiness of the current road networks in urban areas to accommodate the new technology. This study contributes to determining that research on the readiness of the road infrastructure and the deployment of AVs in urban areas is inevitable. It also identifies that roads’ geometric design can dramatically affect AVs’ operation and the difficulties of implementing dedi-cated lanes in urban areas due to space availability.Transport and Plannin
Spatial risk assessment of traffic safety on urban roads
No full textBecause road accidents are still one of the leading causes of death in the world, traffic safety has become a hot topic for policy makers, for the media as well as for academics. One of the main policy aims within this domain is to produce safer roads and, consequently, to reduce the number of (fatal) accidents. In order to make the step from evidence to policy, one needs to make an inventory of the hazardous locations and try to understand the adhering risk on these roads
Developing a Theoretical Framework for Road Safety Performance Indicators and a Methodology for Creating a Performance Index
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i-DREAMS: D9.3 Communication/dissemination plan. Safe tolerence zone calculation and interventions for driver-vehicle-environment interactions under challenging conditions
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Studie naar de effecten van vrij programmeerbare verlichte borden op de verkeersveiligheid.
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i-DREAMS: D9.2 Prototype of project's website. Safe tolerance zone calculation and interventions for driver-vehicle-environment interactions under challenging conditions
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