The Analysis of the Factors Influencing the Severity of Bicyclist Injury in Bicyclist-Vehicle Crashes

Transportation and technological development have for centuries strongly influenced the shaping of urbanized areas. On one hand, it undoubtedly brings many benefits to their residents. However, also has a negative impact on urban areas and their surroundings. Many transportation and technological solutions lead, for example, to increased levels of pollution, noise, excessive energy use, as well as to traffic accidents in cities. So, it is important to safe urban development and sustainability in all city aspects as well as in the area of road transport safety. Due to the long-term policy of sustainable transport development, cycling is promoted, which contributes to the increase in the number of this group of users of the transport network in road traffic for short-distance transport. On the one hand, cycling has a positive effect on bicyclists’ health and environmental conditions, however, a big problem is an increase in the number of serious injuries and fatalities among bicyclists involved in road incidents with motor vehicles. This study aims to identify factors that influence the occurrence and severity of bicyclist injury in bicyclist-vehicle crashes. It has been observed that the factors increasing the risk of serious injuries and deaths of bicyclists are: vehicle driver gender and age, driving under the influence of alcohol, exceeding the speed limit by the vehicle driver, bicyclist age, cycling under the influence of alcohol, speed of the bicyclist before the incident, vehicle type (truck), incident place (road), time of the day, incident type. The obtained results can be used for activities aimed at improving the bicyclists’ safety level in road traffic in the area of analysi

Editorial: Calculation of Passenger Car Equivalents at Roundabouts

Editorial on the Research Topic: Calculation of Passenger Car Equivalents at Roundabouts About this Research Topic: Calculation of Passenger Car Equivalents (PCEs) for heavy vehicles represents the starting point for the operational analysis of road facilities and other traffic management applications. PCEs are used to consider the presence of heavy vehicles in the traffic stream and are expressed as multiples of the effect of an average passenger car. Moreover, the highly curvilinear nature of the roundabout design, both in urban and rural environment, has significant effects on the paths that heavy vehicles would travel; as a consequence, the interaction between the physical and performance characteristics of the heavy vehicles and the geometric features of roundabouts can produce higher impacts on traffic operations than other at-grade intersections. The PCEs at roundabouts can be affected by numerous and specific factors, which include geometric and traffic properties, and other factors (e.g. location and environment, driver behaviour), the effect of which can be significant under conditions of unlimited traffic with high saturation degrees of the traffic streams. Based on these considerations, this Research Topic aims to verify the effect of geometric and traffic-related determinants on the calculation of PCEs for heavy vehicles at modern (i.e. single-lane and multi-lane roundabouts) roundabouts and alternative types of roundabouts (i.e. turbo and flower roundabouts). Since only a few studies were based on field data or have calibrated PCEs for roundabouts, academics and practitioners during the last decade have been using microscopic traffic simulation to calculate the PCEs on roundabouts. Thus, many challenges and research themes are still open for modern and alternative roundabouts, including: how to determine the PCE of different types of vehicle that reflect the actual traffic conditions in presence of motorized and non-motorized vehicles, or how to evaluate the transferability of the Highway Capacity Manual (HCM) recommendations for heterogeneous traffic conditions to adequately explain the traffic complexities of a mixed-traffic state, or how to optimize the working parameters of microscopic traffic simulation models in view of PCEs calculations, or how to assess the likely changes to traffic flow characteristics that may result from the introduction of new technologies for vehicles and how to assess the effects on fleet composition and level of service determinations. This Research Topic welcomes contributions addressing all aspects of simulation of PCEs for modern and alternative roundabouts geared toward solving the above questions. As such, we solicit submissions of research papers dealing with themes that include, but are not limited to: • Prediction of entry lane capacity for roundabouts in heterogeneous traffic conditions and model calibration; • Estimation of capacity for roundabouts based on percentages of heavy vehicles in entering and circulating flows; • Prediction of the entry capacity based on the difference in driver’s gap acceptance behavior between cars and heavy vehicles; • Planning and designing of roundabouts under mixed-traffic flow conditions; • Case studies. https://www.frontiersin.org/research-topics/8991/calculation-of-passenger-car-equivalents-at-roundabout

Safety Evaluation of Turbo-Roundabouts with and without Internal Traffic Separations Considering Autonomous Vehicles Operation

The paper presents a microsimulation approach for assessing the safety performance of turbo-roundabouts where Cooperative Autonomous Vehicles “CAVs” have been introduced into the traffic mix alongside conventional vehicles “CVs”. Based on the analysis of vehicle trajectories from VISSIM and subsequent analysis of traffic conflicts through the Surrogate Safety Assessment Model (SSAM), the research aims to evaluate the safety benefits of turbo-roundabouts where the lanes are physically separated by raised curbs, compared to roundabouts without such curbs. The paper will then describe the methodological path followed to build VISSIM models of turbo-roundabouts with and without raised curbs in order to calibrate the simulation models and estimate the potential conflicts when a higher percentage of CAVs are introduced into the traffic mix. A criterion has been also proposed for setting properly the principal SSAM filters. The results confirmed both higher safety levels for turbo-roundabouts equipped with raised lane dividers compared to turbo-roundabout solutions without curbs, and better safety conditions under the traffic mix of CVs and CAVs. Therefore, it follows that, in absence of crash data including CAVs, the surrogate measures of safety are the only approach in which the safety performance of any roundabout or road entity can be evaluated

Estimation of Passenger Car Equivalents for Two-Lane and Turbo Roundabouts Using AIMSUN

The paper addresses issues related to Passenger Car Equivalents (PCEs) at roundabouts. Compared to other road units, the curvilinear elements of roundabout geometric design may impose greater constraints on vehicular trajectories and have a significant effect on the swept envelope of heavy vehicles. Specifically, the aim of the paper is to present the methodological approach which used traffic microsimulation to estimate PCEs. Focus is made on a case study which considered the conversion of a two-lane roundabout into a basic turbo roundabout with comparable size. Empirical capacity functions for both roundabouts were derived as target values to which simulated capacities by lane were compared. In order to estimate the PCEs a criterion of equivalence based on the amount of capacity used by cars and heavy vehicles is presented. AIMSUN allowed to simulate traffic conditions with different percentages of heavy vehicles at both roundabouts. Thus, variation of traffic conditions where mixed fleets operate was explored. A comparison was made between the PCEs estimated for each entry lane characterized by similar mechanism of entry maneuver. The results indicated there is a need to distinguish the impact of heavy vehicles when operational performance of a two-lane roundabout or a turbo-roundabout should be examined. Especially when circulating flows increase, a higher PCE value is expected than the value that the Highway Capacity Manual proposes for roundabouts

The relevance of on-road emission monitoring in different type of roundabouts in rural roads

Road traffic significantly contributes to urban air pollution as means of particulate matter (PM) and nitrogen oxides (NOX) emissions [1]. Despite the deployment of clean powertrains, internal combustion engines are the most widely used technology in the European Union; gasoline- and diesel-fueled represented around 90% of passenger cars sold between 2014 to 2017 [2]. The amount of exhaust gases emitted by motor vehicles depend on speed profile, vehicle type, traffic volumes and intersections [3]. Roundabouts have been considered and built around the world to replace intersections previously controlled by traffic lights as a means of improving operational performance, at least in certain flow range [4]. These latter ones are considered pollution hotspots locations, due to speed changes cycle around them [5] [6]. Despite the demonstrated benefits in terms of traffic flow, delay reducing and safety [7], roundabouts raised some doubts concerning emissions performance [8]. Bearing this in mind, this paper compares vehicle activity and on-road emission data in three different roundabouts in rural roads: a compact two-lane, a multi-lane and a single lane roundabout in Aveiro, Portugal. It was hypothesized that carbon dioxide (CO2) and NOx emissions, engine speed and the relative positive acceleration (RPA) are impacted by the differences in the approaching and conflicting traffic volumes, the volume-to-capacity ratio and the roundabout layout. Input data such as approaching and circulating traffic volumes, and queue length were collected by videos cameras installed at the studied locations. Field measurements were carried out with two light duty vehicles (gasoline and diesel), using a Portable Emissions Measurement System (PEMS) to measure CO2 and NOX volumetric concentrations. Alongside, an OBD-II scan interface record vehicle speed data, engine speed and acceleration. After that, a relationship between congestion level of roundabouts and occurrence of each speed profile (no stop – I, stop once – II and multiple stops – III) was established, using discrete choice models. Finally, discrete choice models obtained from single-lane, compact two-lane and multi-lane roundabouts were compared. The methodology and models developed used in this paper can be applied by simply measuring roundabout traffic volumes by means of discrete choice models that allows simultaneously detecting differences in location and variability characteristics of the distributions of the observations taken at roundabouts. It also allows to identify some relevant operational and design features of a rural roundabout prior its implementation to enhance capacity and emissions fields.publishe

Microsimulation-based passenger car equivalents for heavy vehicles driving turbo-roundabouts

Due to its geometric design, turbo-roundabouts impose greatest constraints to the vehicular trajectories; by consequence, one can expect a more unfavourable impact of heavy vehicles on the traffic conditions than on other types of roundabouts. The present paper addresses the question of how to estimate Passenger Car Equivalents (PCEs) for heavy vehicles driving turbo-roundabouts. The microsimulation approach used revealed as a useful tool for evaluating the variation of quality of traffic in presence of mixed fleets (different percentages of heavy vehicles). Based on the output of multiple runs of several scenarios simulation, capacity functions for each entry lane of the turbo-roundabout were developed and variability of the PCEs for heavy vehicles were calculated by comparing results for a fleet of passenger cars only with those of the mixed fleet scenarios. Results show a dependence of PCEs for heavy vehicles on operational conditions, which characterise the turbo-roundabout. Assuming the values of PCEs for roundabouts provided by the 2010 Highway Capacity Manual (HCM), depending on entering manoeuvring underestimation and overestimation of the effect of heavy vehicles on the quality of traffic conditions have been found

Assessing the Environmental Performances of Urban Roundabouts Using the VSP Methodology and AIMSUN

In line with globally shared environmental sustainability goals, the shift towards citizen-friendly mobility is changing the way people move through cities and road user behaviour. Building a sustainable road transport requires design knowledge to develop increasingly green road infrastructures and monitoring the environmental impacts from mobile crowdsourced data. In this view, the paper presents an empirically based methodology that integrates the vehicle-specific power (VSP) model and microscopic traffic simulation (AIMSUN) to estimate second-by-second vehicle emissions at urban roundabouts. The distributions of time spent in each VSP mode from instantaneous vehicle trajectory data gathered in the field via smartphone were the starting point of the analysis. The versatility of AIMSUN in calibrating the model parameters to better reflect the field-observed speed-time trajectories and to enhance the estimation accuracy was assessed. The conversion of an existing roundabout within the sample into a turbo counterpart was also made as an attempt to confirm the reproducibility of the proposed procedure. The results shed light on new opportunities in the environmental performance evaluation of road units when changes in design or operation should be considered within traffic management strategies and highlighted the potential of the smart approach in collecting big amounts of data through digital communities

conversion of existing roundabouts into turbo roundabouts case studies from real world

Compared with roundabouts the main advantages of turbo-roundabouts are the reduction in the number of potential conflicting points and the lower speed of vehicles passing through the intersection, they both can improve safety conditions at the junction. Moreover, the physical delimitation among lanes limits the side-by-side accident risk. These aspects make turbo-roundabouts more appropriate than roundabouts when a higher level of safety has to be guaranteed, particularly in presence of relevant pedestrian and two-wheels traffic volumes. The present paper has three main objectives: (1) to discuss general design criteria and functional principles of turbo roundabouts, (2) to give the geometric design principles of the central island and circulating lanes and (3) to present three case studies from real world concerning the conversion of existing roundabouts into turbo roundabouts

A multi-element psychosocial intervention for early psychosis (GET UP PIANO TRIAL) conducted in a catchment area of 10 million inhabitants: study protocol for a pragmatic cluster randomized controlled trial

Multi-element interventions for first-episode psychosis (FEP) are promising, but have mostly been conducted in non-epidemiologically representative samples, thereby raising the risk of underestimating the complexities involved in treating FEP in 'real-world' services

Future Development of an Energy-Efficient Electric Scooter Sharing System Based on a Stakeholder Analysis Method

E-scooters as a new form of mobility are gaining more and more popularity. This popularity results from the flexibility of this mode of transport, but above all from the positive impact on the natural environment through the much higher energy efficiency of an e-scooter compared to a motor vehicle (according to the literature the rate is 2 km per kWh equivalent for a motor vehicle and the range is 90–100 km per kWh in the case of an e-scooter). This paper introduces a discussion on the future development of an energy-efficient electric scooter sharing system based on stakeholder analysis methods. The implementation of the e-scooter sharing system involves linking several areas of human activity, including social activity. This, in turn, relates to the interactions and building of relationships with entities, particularly those influencing the provision of services and their effects. The large number of entities and the complexity of the relations between them make it a challenge both to identify stakeholders in the development of the public e-scooter system and to indicate their roles in shaping the sustainable development strategy for urban mobility. The following study was based on the methodological foundations of stakeholder theory and social network analyses. The main research objective of the article is to identify and assign to different groups the stakeholders influencing the sustainable development of energy-efficient e-scooter sharing systems based on Polish cities. An evaluation was carried out using expert methods with a stakeholder analysis, based on matrix and mapping methods, and with the MACTOR application. Relationships and cooperation suggestions were established for each of the stakeholder groups, which could become an important part of the strategic approach to supporting public transport service providers and organizers, as well as allowing for further reductions in energy consumption in the city by introducing such services on a large scale. The cooperation of the entities participating in the implementation of bike-sharing services can contribute to their greater sustainable development and assurance using the new mobility modes, which consume less energy and at the same time make the city energy-efficient