Inclusive and collaborative advanced transport: are we really heading to sustainable mobility?

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Optimal Location of Electronic Toll Gantries: The Case of a Portuguese Freeway

AbstractThis paper presents a decision supporting tool for the location of electronic toll gantries in freeways, regarding the maximization of the toll revenue. The adopted case study consists in one of the most important Portuguese freeways, with 180km of extension and a recently introduced electronic toll collection system. In the first stage of the modeling procedure, we applied a categorical binary model to set drivers’ route choice between the tolled freeway segments and the fastest non-tolled alternative paths, based on traffic data collected before and after the introduction of the toll fees. Then, we developed an optimization model to assign a limited or unlimited number of toll gantries to the freeway segments considering the generalized costs of the trips performed using the freeway and the alternative routes. The results showed that charging for all of the freeway segments may not be the best solution to increase road pricing revenue

Urban Road Crashes and Weather Conditions: Untangling the Effects

Most previous studies show that inclement weather increases the risk of road users being involved in a traffic crash. However, some authors have demonstrated a little or even an opposite effect, observed both on crash frequency and severity. In urban roads, where a greater number of conflict points and heavier traffic represent a higher exposure to risk, the potential increase of crash risk caused by adverse weather deserves a special attention. This study investigates the impact of meteorological conditions on the frequency of road crashes in urban environment, using the city of Porto, Portugal as a case study. The weather effects were analyzed for different types of crashes: single-vehicle, multi-vehicle, property-damage-only, and injury crashes. The methodology is based on negative binomial and Poisson models with random parameters, considering the influence of daily precipitation and mean temperature, as well as the lagged effects of the precipitation accumulated during the previous month. The results show that rainy days are more prone to the occurrence of road crashes, although the past precipitation may attenuate such effect. Temperatures below 10 degrees C are associated with higher crash frequencies, complying with the impacts of precipitation in the context of the Portuguese climate characteristics

¿Qué caballos son aquellos que hacen sombra en el mar?

Tradução espanhola do romance Que cavalos são aqueles que fazem sombra no mar?, de António Lobo Antunes, com © em castelhano para todo o mundo, realizada por Antonio Sáez Delgado

Takeover performance evaluation using driving simulation: a systematic review and meta-analysis

Introduction: In a context of increasing automation of road transport, many researchers have been dedicated to analyse the risks and safety implications of resuming the manual control of a vehicle after a period of automated driving. This paper performs a systematic review about drivers' performance during takeover manoeuvres in driving simulator, a tool that is widely used in the evaluation of automated systems to reproduce risky situations that would not be possible to test in real roads. Objectives: The main objectives are to provide a framework for the main strategies, experimental conditions and results obtained by takeover research using driving simulation, as well as to find whether different approaches may lead to different outcomes. Methodology: First, a literature search following the PRISMA statement guidelines and checklist resulted in 36 relevant papers, which were described in detail according to the type of scenarios and takeover events, drivers' engagement in secondary tasks and the assessed takeover performance measures. Then, those papers were included in a meta-analysis combining PAM clustering and ANOVA techniques to find patterns among the experimental conditions and to determine if those patterns have influence on the observed takeover performance. Conclusions: Less complex experiments without secondary task engagement and conducted in low-fidelity simulators are associated with lower takeover times and crash rates. The takeover time increases with the time budget of the first alert, which reduces the pressure for a driver's quick intervention. (c) 2021, The Author(s)

Free-gap evaluation for two-lane rural highways

Studies related to operating speed predicting models' development require vehicles' speed under free-flow conditions to be collected at different sites. Thus, a critical issue is the definition of the gap (or headway) from which the speed of one vehicle is not affected by the speed of the vehicle ahead. In many studies, a 5-s headway was adopted as the reference headway value from which a vehicle could be assumed to travel at a free-flow speed. Justifications for this value's application are not clearly presented in the literature, and some authors suggest the use of other reference values. This paper presents a definition for platoon from observed values of vehicles' time gap. The reference gap value between two successive vehicles considered as traveling in a nonplatoon condition is defined as "free gap." A five-step methodology is described and tested for road conditions in Portugal. The application performed showed both the adequacy of the methodology proposed and the convenience of exploratory studies aimed at the identification of platoon gap (or headway) suitable for specific operating speed studies. According to the methodology proposed, a 6-s gap is a suitable reference for future data collection on operating speed on Portuguese roads. This result suggests the need to review the headway reference values found in the literature for representing free-flow general conditions