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Electric Micromobility (EM) and the use of dockless shared electric scooters (DSES) has rapidly grown in many cities worldwide. They are promoted as an accessible, low-emissions, versatile, and low-effort alternative. This article conducts a systematic review of DSES, considering their evolution, operation, regulations, user profile, environmental impact, safety, and pricing. The review shows age, income, and gender gaps among their users as most of them are young, male, high-income adults. DSES adopters come mainly from public transport, walking, and cycling. Their environmentally friendly label needs to be analyzed according to the city's context; their distribution and collection logistics impacts, and the vehicle's service life. The review shows significant differences in the way cities have regulated the service. One of the most significant potential contributions from DSES to urban mobility is the possibility to be integrated with public transport, implementing the Mobility-as-a-Service concept. [ABSTRACT FROM AUTHOR]

The global COVID-19 outbreak has demanded drastic actions and policies from the governments and local authorities to stem the spread of the virus. Most of the measures involve behavioural changes from citizens to reduce their social contact to a minimum. Thus, these actions influence individual activity patterns and transport systems in different ways. This paper studies the short-term impacts on the transport system caused by the different policies adopted by the Colombian government and local authorities to contain the COVID-19 spread. Using official and secondary data concerning the seven most populated cities in Colombia, we analyse the impacts on three components of the transport system: air transport, freight transport, and urban transport. Results show that national policies and local decisions have decreased the demand for motorised trips across the cities, diminishing congestion levels, reducing transit ridership, and creating a reduction in transport externalities. The country banned air transport for passengers and only allowed air cargo for medical and necessary supplies, which will have negative consequences for the economics of the airline industry. During the first three months of the COVID-19, freight was the most resilient transport component. However, freight trips diminished around 38%, affecting mainly the supply chain of nonessential products. During the pandemic, governments need to provide subsidies to maintain the system supply to avoid crowdedness and promote active transport by allocating less-used street space to cyclists and pedestrians. In the short term, transportation service providers will face a financial crisis, deepened by the pandemic, which will require government assistance for their recovery. [ABSTRACT FROM AUTHOR]

There is a considerable gap between the existing knowledge used to estimate the value of time in passenger transport when compared with the framework of analysis developed for freight transport. In this paper, we applied a model that is gaining recognition in the context of passenger values of time estimation known as random valuation (RV) to a context in which there is little evidence of its application: freight value of time estimation (FVOT). Secondly, we compared this model to the commonly used methodology, random utility (RU). We analysed several levels of model specification to estimate the FVOT using data from a stated choice experiment applied in five of the main cargo transport road corridors of Colombia. The analysis accounts for the value of time differentiated by vehicle type. Results suggest that the RV models performed better for the same dataset than its counterpart RU in all cases. Another aspect to highlight is that the FVOT value obtained with the RU approach was pretty similar to those obtained with the RV in most cases. Also, the estimates FVOT for empty trips are closer, and in some cases higher, than those of loaded trips. [ABSTRACT FROM AUTHOR]

Transportation networks and systems are vulnerable to natural disasters. During disaster response operations, the degraded functionality of the system can negatively impact the affected population because disrupting relief activitiesincreases human suffering resulting from the lack of access to essential goods or services. Mathematical formulations for assessing transportation network vulnerability do not generally consider this lack of access or deprivation costs, and can lead to inappropriate strategies for humanitarian assistance. This paper proposes a transportation network vulnerability assessment model that allows identifying critical links for the development of high impact disaster response operations. The model is based on an economic analysis that considers the logistical costs of the distribution operations and the external effects derived from the delays in the provision of basic supplies (deprivation costs). The approach is particularly useful for planning resilient disaster response plans in the preparednessstage, prioritizing investment for mitigation and adaptation, and prioritizing the rehabilitation (access restoration) of the disrupted links in the response and recovery stages. In addition to numerical experiments using case study networks, the authors implemented the model to the coffee-producing region of Colombia, which was hit by an earthquake in 1999. [ABSTRACT FROM AUTHOR]

This paper aims to evaluate the influence of policies, attitudes and perceptions when incentivizing alternative fuel vehicles. The impact of possible policies such as gasoline taxes increases, purchase price subsidies, tax exemptions, and increases in fuel recharging station availability for alternative fuelled vehicles is evaluated using hybrid choice models. The models also allow assessing the sensitivity of latent variables (i.e., attitudes and perceptions) in the car purchase behaviour. The models are estimated using data from a stated choice survey collected in five Colombian cities. The latent variables are obtained from the rating of statements related to the transport system, environmental concern, vehicle preferences, and technology. The modelling approach includes regression between latent variables. Results show that environmental concern and the support for green transport policies have a positive influence on the intention to purchase alternative fuel vehicles. Meanwhile, people who reveal to be car-dependent prefer to buy standard fuelled vehicles. The analysis among cities shows similar trends in individual behaviour, although there are differences in attribute sensitivities. The policy scenario analysis revealed high sensitivity to capital cost and the need for extensive investments in refuelling stations for alternative fuel vehicles to become attractive. Nevertheless, all policies should not only be directed at infrastructure and vehicles but also be focused on user awareness and acceptance of the alternative fuel vehicles. The analysis suggests that in an environmentally conscious market, people prefer alternative fuels. However, if the transport policies support private transport, the market shares of alternative fuel vehicles will decrease. [ABSTRACT FROM AUTHOR]

Literature has focused on studying port choice independently or as an element of a supply chain without considering the joint selection with the country of origin/destination of the imports/exports. However, the characteristics and location of a port may make it more attractive to mobilise more freight from/to some particular countries rather than others, making the port choice decision dependent on the country of origin/destination of the cargo. This article proposes advanced econometric models to evaluate simultaneously port choice and the country of origin/destination choice for Colombian imports and exports. Findings suggest that for imports and exports domestic freight rate is the most important variable for the joint choice process. Also, for exports, maritime transit time is more relevant than for imports, while for the frequency of shipping lines the opposite is true. The existence of a trade agreement and the gross domestic product per capita also have a significant influence on the election of a country for exports/imports. [ABSTRACT FROM AUTHOR]

Signal plan transition is the process of changing from one timing plan to another. It begins when the first intersection starts adjusting signal timing plans and ends when the last intersection completes adjusting signal timing plans. The transition between signal timing plans is required because traffic patterns change during the day. Therefore, it is necessary to modify signal timing parameters offset, phase split, and cycle length for different expectations of traffic volume. This paper presents an alternative and new mathematical model to enhance the performance of traffic signals coordination at intersections during the transition phase. This model is oriented to describe the transition regarding coordination parameters in all intersections of an arterial road for minimizing the social cost during the transition phase expressed in function of costs due to delays, fuel consumption, and air emissions. An ant colony algorithm was designed, coded, and simulated to find the optimal transition parameters using available data. The model was evaluated based on its ability to minimize social costs during the transition period. Results showed that the proposed method performs better than traditional ones. [ABSTRACT FROM AUTHOR]

This paper details research to design an estimation process for Deprivation Cost Functions (DCF) using Contingent Valuation, and to apply it econometrically to obtain a DCF for drinkable water. The paper describes both the process and results obtained. The results indicate that deprivation costs for drinkable water have a non-linear relation with deprivation times. The estimated DCFs provide a consistent metric that could be incorporated into humanitarian logistic mathematical models, eliminating the need to use proxy metrics, and providing a better way to assess the impacts of delivery options and actions. The research reported in this paper is the first attempt in the literature to produce estimates of the economic value of human suffering created by the deprivation of a critical supply or service. [ABSTRACT FROM AUTHOR]

The transition phase is generally defined as the process of switching from one timing plan to another; this process may include changes in offset, phase split or cycle length until coordination for a new timing plan is reached once again. As noted in the literature, transition phases between timing plans may lead to severe disruptions of traffic flow, resulting in potentially lasting effects. The aim of this paper is to comprehensively review, classify and analyse the literature regarding transition between different timing plans to highlight existing research gaps and give researchers a starting point to continue contributing with solutions to the transition problem. Regarding transition approaches, a gap concerning mathematical approaches was deemed significant as a transition could be greatly benefited by simultaneously optimising more than one operational measure of effectiveness through multi-objective mathematical models. Moreover, in the analysis of applied approaches, Shortway algorithms generally outperformed other practical methods under different scenarios. [ABSTRACT FROM PUBLISHER]

A fluid-pressured test has been developed as an alternative to measure tensile strength of concrete. This test method covers the determination of the tensile strength of cylindrical concrete specimens with a centered internal hole where a radial internal fluid pressure is applied until failure occurs. This loading condition induces tangential stresses on the specimen; the maximum fluid pressure sustained by the specimen is affected by appropriate geometric factors to obtain a measurement of the tensile strength. Preliminary experimental data suggests that the tensile strength measured with the proposed method is about 17% greater than the tensile strength obtained from splitting tensile tests. Additionally, results of the tensile pressure strength were on average 11% of the compressive strength. [ABSTRACT FROM AUTHOR]

This paper considers a practical variant of the Vehicle Routing Problem (VRP) known as the Heterogeneous Vehicle Routing Problem with Time Windows and Multiple Products (HVRPTWMP). As the problem is NP-hard, the resolution approach proposed here is a sequential Ant Colony System (ACS)-Tabu Search algorithm. The approach introduces a two pheromone trail strategy to accelerate agents' (ants) learning process. Its convergence to good solutions is given in terms of fleet size and travel time while completing tours and service to all customers. The proposed procedure uses regency and frequency memories form Tabu Search to further improve the quality of solutions. Experiments are carried out using instances from literature and show the effectiveness of this procedure. [ABSTRACT FROM AUTHOR]