Background: Recent technological advancements in automated vehicles are becoming more popular, especially in developed and emerging markets. These changes are bringing new challenges for the drivers, planners, engineers, and manufacturers. Due to several crash incidents that occurred over the past years involving driverless vehicles, safety concerns of potential users have been raised. One key aspect is to design the system so that the user experience can be improved, especially in terms of safety and reliability. User's viewpoint can also be used to collect feedback about the system based on their experience and interaction with the technology. Public opinion surveys have been frequently used to capture such feedback. In this context, this recently completed survey study investigates the opinion, trust, and expectations of potential users in Belgium, particularly on driverless vehicles' safety performance. Methods: Various safety critical driving scenarios were designed to obtain a more detailed understanding of the public's safety perceptions. Participants were asked to provide their assessment on automated driving systems' safety performance under those scenarios in a stated preference survey. Results: Total 360 people participated in the survey. Those who provided demographic information included 64.1% male and 34.8% female, out of which almost 70% had bachelor’s level education or above. Several demographics such as age, education level, income level, owning a car, driving experience, frequency of driving, and previous experience with automated functions, were found to have a significant association with the public's interest and trust in the safety performance of the system. Overall, most of the respondents were optimistic regarding the system's reliability for making efficient and safe decisions (e.g., avoiding a potential collision) under various critical traffic scenarios. Driving on motorways was the most trusted scenario (90% agreement) for automated vehicle operation. Situations where respondents indicated concern or lesser trust in the technology included the presence of a large number of vulnerable road users (41%), driving in poor visibility due to weather conditions (41.6%), and driving through work zones (46%). Conclusions: The results offer unique challenges to designers, technology developers, planners, and manufacturers about developing such systems and strategies that would lead to the safe and successful adaptation of future automated vehicles. The willingness to pay for getting an automated vehicle was also correlated with trust in the system's safety performance. The study's findings suggest further exploration of users' understanding, trust, and safety expectations of the driverless vehicle technology for successful deployment and adaptation.@en

Cooperative, Connected and Automated Mobility (CCAM) enabled by Connected and Autonomous Vehicles (CAVs) has potential to change future transport systems. The findings from previous studies suggest that these technologies will improve traffic flow, reduce travel time and delays. Furthermore, these CAVs will be safer compared to existing vehicles. As these vehicles may have the ability to travel at a higher speed and with shorter headways, it has been argued that infrastructure-based measures are required to optimise traffic flow and road user comfort. One of these measures is the use of a dedicated lane for CAVs on urban highways and arterials and constitutes the focus of this research. As the potential impact on safety is unclear, the present study aims to evaluate the safety impacts of dedicated lanes for CAVs. A calibrated and validated microsimulation model developed in AIMSUN was used to simulate and produce safety results. These results were analysed with the help of the Surrogate Safety Assessment Model (SSAM). The model includes human-driven vehicles (HDVs), 1st generation and 2nd generation autonomous vehicles (AVs) with different sets of parameters leading to different movement behaviour. The model uses a variety of cases in which a dedicated lane is provided at different type of lanes (inner and outer) of highways to understand the safety effects. The model also tries to understand the minimum required market penetration rate (MPR) of CAVs for a better movement of traffic on dedicated lanes. It was observed in the models that although at low penetration rates of CAVs (around 20%) dedicated lanes might not be advantageous, a reduction of 53% to 58% in traffic conflicts is achieved with the introduction of dedicated lanes in high CAV MPRs. In addition, traffic crashes estimated from traffic conflicts are reduced up to 48% with the CAVs. The simulation results revealed that with dedicated lane, the combination of 40-40-20 (i.e., 40% human-driven – 40% 1st generation AVs– 20% 2nd generation AVs) could be the optimum MPR for CAVs to achieve the best safety benefits. The findings in this study provide useful insight into the safety impacts of dedicated lanes for CAVs and could be used to develop a policy support tool for local authorities and practitioners.@en

Mobility and environmental benefits of Green Light Optimal Speed Advisory (GLOSA) systems have been reported by many previous research studies, however, there is insufficient knowledge on the safety implications of such an application. For safe deployment of GLOSA system, it is most critical to identify and address potential safety issues in the design process. It can be argued that implementation of GLOSA system can improve safety by reducing traffic conflicts associated with the interrupted traffic flow at signalised intersections. However, more research findings are needed from field and simulation based studies to evaluate the impacts on safety under a variety of real-world scenarios. As part of the LEVITATE (Societal Level Impacts of Connected and Automated Vehicles) project under European Union's Horizon 2020 Programme, the main objective of this study is to examine the safety impacts of GLOSA under mixed traffic compositions with varying market penetration rates (MPR) of connected and automated vehicles (CAVs). A calibrated and validated microsimulation model (developed in Aimsun) of the greater Manchester area was used for this study where three signalised intersections in a corridor were identified for implementing GLOSA system. An improved algorithm was developed by identifying the potential issues/limitations in some of the GLOSA algorithms found in literature. Behaviours of CAVs were modelled based on the findings of a comprehensive literature review. Safety analysis was performed through processing the simulated vehicular trajectories in the surrogate safety assessment model (SSAM) by the Federal Highway Administration (FHWA). The surrogate safety assessment results showed small improvement in safety with the GLOSA implementation at multiple intersections in the test network only at low MPR (20%) scenarios of CAVs, as compared to the respective without GLOSA scenarios. No or rather slightly lower improvement in safety was observed with GLOSA implementation under mixed fleet scenarios with 40 % or higher 1st Generation or 2nd Generation CAVs, as compared to the respective scenarios without GLOSA. The implementation of GLOSA system was also found to have some impact on the traffic conflict types (although not consistent across all MPR scenarios), where rear-end conflicts were found to decrease while a slight increase was observed in lane-change conflicts.@en

Connected, Cooperative and Automated Mobility (CCAM) are expected to be introduced in increasing numbers over the next decade based on the rapidly developing capability of modern technologies. The need for policies around the introduction of CCAM is starting to arise, based on the evaluation of the likely impact of different technologies, with the aim to capture the benefits of automation and ensure that new technologies contribute to wider policy objectives. The Horizon 2020 Levitate project aims to investigate the potential short, medium and long term impacts of CCAM, through an innovative multi-disciplinary impact assessment methodology, which will be incorporated within a new web-based policy support tool to enable city and other authorities to forecast impacts of CCAM on urban areas. The aim of the present paper is to provide an insight on the development of the Levitate Policy Support Tool (PST), the use cases, parameters and impacts considered and the methodologies applied for the estimation of relationships and impacts of connected and automated transport systems. This policy support tool will comprise a knowledge and an estimator module and will include forecasting and backcasting systems providing estimates for different types of impacts and allowing comparative analyses. The Policy Support Tool will integrate the methodologies and findings of the Levitate project, in order to develop an overall framework for the assessment of impacts, benefits and costs of CCAM for different automation and penetration levels and on different time horizons, as well as a public toolkit and a decision support system allowing the testing of various policy scenarios on the basis of the needs of relevant stakeholders.@en

Safety evaluation is a critical aspect through the future stages of automation development. Since there is a lack of historical and generalizable safety data in high levels of Connected and Autonomous Vehicles (CAVs), a possible approach to follow is the microscopic simulation method. Through microsimulation, vehicle trajectories are able to be exported and traffic conflicts to be identified using the Surrogate Safety Assessment Model (SSAM). Therefore, it is crucial to develop techniques in order to analyze conflict data extracted from microsimulation and evaluate crash data aiming to support road safety applications of automation technologies. This paper attempts to propose a safety evaluation approach for estimating crash rate of CAVs through microsimulation. For this purpose, the city center of Athens (Greece) was modelled using the Aimsun Next software paying attention to the calibration and validation of the model using real data of traffic characteristics. Moreover, different scenarios were formulated concerning different market penetration rates (MPRs) of CAVs and two fully automated generations (1st and 2nd generation) were simulated for modelling them. Subsequently, the SSAM software was used in order traffic conflicts to be identified and then converted to crash rate. Analysis of the outputs along with traffic data and network geometry characteristics were then conducted. The results indicated that in higher CAV MPRs, crash rates will be significantly lower as well as when the following-vehicle in the occurred conflict is a 2nd generation CAV. Lane change conflicts caused the highest crash rates compared to rear-end conflicts, which presented the lowest rates.@en

Raising parking charges is a measure that restricts the use of private vehicles. With the introduction of connected and autonomous vehicles (CAVs), the demand for parking has the potential to reduce as CAVs may not park at ‘pay to park’ areas as they are able to “cruise” or return home. However, it might not be financially feasible for them to return to their origin if the destination region is far away. Therefore, the question is: how could we develop parking policies in the CAVs era? To determine the best parking strategy for CAVs, four scenarios were tested in this paper: (i) enter and park within the destination area, (ii) enter, drop off, and return to the origin, (iii) enter, drop off, and return to outside parking and (iv) enter and drive around. Since real-world parking demand data for CAVs are not available, a simulation model of the road network in Santander (Spain) was employed to collect data on both CAV operations (e.g., conservative versus aggressive behaviors) and parking choices. Multinomial logistic regression model was used to identify the best parking option for CAVs. Performance indicators such as traffic, emissions, and safety were employed to compare the performance of a range of parking alternatives. It was found that the balanced scenario (i.e., combination of all parking choices) performs better with the greatest change in delay (around 32%). With 100% CAV market penetration, traffic crashes were reduced by 67%. This study will help local authorities formulate parking policies so that CAVs can park efficiently.@en

Shared Automated Vehicles (SAVs) hold great promise for the future of urban mobility. Automated ride-sharing services are expected to alleviate traffic congestion, reduce traffic emissions, and significantly improve road safety by combining advanced connected and autonomous vehicle (CAV) technology with the ride and/or car-sharing concept. These benefits, however, are highly dependent on the deployment concept of the service and environment including network characteristics, CAV technology, traffic compositions, population acceptance, etc.. This study aims to assess the mobility and environmental impacts of introducing a door-to-door automated ride-sharing (ARS) service under different deployment scenarios. Two calibrated and validated city-scale networks with different characteristics were used: a suburban area in Great Manchester (UK) and a city-centre area in Leicester (UK). An optimisation technique for the vehicle routing problem was developed to efficiently operate ARS at a network-level. The preference of customers for individual and shared rides, Willingness to Share (WTS) was investigated to gain a better understanding of the impact of utilisation choice based on the performance indicators (i.e., delay, travel time, speed, kilometres-driven and emissions). The introduction of ARS was investigated under two deployment scenarios: 1) mixed with conventional human-driven vehicles (HDVs) and 2) mixed with HDVs with varying CAV market penetration rates. Findings suggest that introducing ARS can adversely impact mobility and the environment under mixed traffic, especially in suburban areas, and the benefits of an automated ride-sharing system are highly dependent on WTS. The findings will assist local authorities in formulating automated ride-sharing policies to manage the traffic on roads.@en

This study aims to quantify the safety impacts of Connected and Automated Vehicles (CAVs) in mixed traffic environments in three calibrated and validated urban road networks including Manchester (UK), Leicester (UK), and Athens (GR). Road safety impacts were investigated through traffic microsimulation techniques combined with application of the Surrogate Safety Assessment Model (SSAM). Behaviours of CAVs were modelled based on a comprehensive literature review and discussions with experts. The estimated number of conflicts, extracted from the microsimulation and SSAM approach, were converted to the number of crashes by using a probabilistic method. Results revealed a significant improvement in case of passenger car fleet scenarios in all three test networks. However, the mixed fleet scenarios involving freight and public transport vehicles showed added complexities due to non-homogeneity in vehicle characteristics. In this context, limitations of microsimulation and SSAM have also been identified while recommendations have been made for methodological improvements. Overall, the findings of this research provide several useful insights by using a practical procedure to estimate safety impacts under mixed traffic environment. Future research and field trials should focus on addressing the challenges of maintaining safety in the early and transition phases of the deployment of CAVs.@en

Rapid technological advances leave limited margins for the preparation of cities to receive Connected, Cooperative and Automated Mobility (CCAM). The LEVITATE project endeavours to develop an open access web-based Policy Support Tool (PST), that will provide decision makers at all levels with access to LEVITATE methodologies and results. The aim of the PST is to consolidate the outputs of different methods into an overall framework for the assessment of impacts, benefits and costs of CCAM, for different automation and penetration levels and on different time horizons. The PST comprises two modules: the Knowledge and the Estimator module, which includes a forecasting and a backcasting sub-system. The present research provides an insight of the PST, by presenting the studied automation use cases, parameters and impacts of CCAM, the applied methodologies and the online tool.@en

New technologies in the transport sector promise to bring about certain benefits, for example related to mobility or safety, but are also expected to cause negative side effects which are in conflict with strategic city objectives. These might be mitigated by appropriate policy interventions that are designed carefully and timely. The Horizon 2020 research project LEVITATE has investigated multiple impacts of connected and automated transport systems, using an integrated multi-method approach, ranging from microscopic and mesoscopic simulations to system dynamics and Delphi panels. In particular, the system dynamics model described in this paper served to assess several systemic and wider impacts that were found difficult or even impossible to assess with the other methods. The main parts of the model are a population sub-model, a simplified traffic demand model distinguishing between three modes of transport, and a model for the use of public space. In order to calibrate the model and get results that are consistent with those of other methods, the input and output data of those simulations have also been incorporated into the system dynamics model. By means of selected example impact variables – modal split, demand for parking space and average commuting distance – the obtained effect of increasing automation as well as of several policy interventions is demonstrated.@en

Access management strategies are devised to facilitate travel mobility and improve safety. Direct access especially left-turns in and out of developments can create significant problems for the traffic flow and safety on the adjacent roadway and at the driveways. This study evaluates the safety and operational impacts under various access configurations, and provides basic guidelines as to when left-turns at driveways should be prohibited. The safety considerations were found to be less significant compared to the operational concerns since the crash reductions that might be expected from access restrictions appeared to be relatively modest. The importance of review of crash history by site is emphasized. Traffic simulation models were developed using VISSIM to analyze the operational impacts of driveway turning restrictions at corner and mid-block sites. The results indicate that lesser the corner clearance, more negative is the impact on driveway related delays. Also, the negative impact due to mainline volume increment was more severe as compared to the increment in driveway volume. The impact on the driveway operations was worse when the number of lanes on the adjacent roadway was less than 5 or 4. The right-turn (in or out) driveway traffic was not critical from either the operations or safety perspectives due to fewer conflict points. General guidelines are proposed for prohibition of left-turns in and out for various combinations of mainline and driveway traffic volumes and corner clearances.@en

Technological advancements are continuously changing the human life. Like many other developments, autonomous vehicle system is attracting public interest and being widely discussed by all the stakeholders. Recent reports show that in future, autonomous vehicles or self-driving cars will be on roads in developed countries such as in UK and US. In this age of information technology, advancements made in developed countries not only move to the developing countries but also impact the opinions and lives of the people living in these countries. Therefore, there is a need to develop more effective strategies which can help the adaption of upcoming technologies in transport systems like autonomous vehicles. In this respect, user’s perception becomes highly significant as this can help designers by providing them the information about real time issues and human observations. Up till now, no significant work has been carried out on exploring the user’s perception about autonomous vehicles in developing countries like Pakistan. This study aims at capturing the user’s view point about the use of autonomous vehicles which can provide relevant information on perceived benefits and challenges in user’s perspective. An underlying objective is also to compare this perspective with developed countries like US, UK, and Australia etc. Findings of the study will help in assessing user’s perceptions in terms of challenges, the level of awareness and understanding about autonomous vehicles. It will lead to shaping up the strategies to address the needs of users so that more viable and equally acceptable technological interventions can be made.@en

Children in developing countries are exposed to greater risk of fatality, serious injury, or disability, during road travel due to lack of awareness and absence of laws on children road safety measures such as the use of child restraints in vehicles. In most of the developing countries, it is not required by law, to use child car seats and therefore are rarely used. Research studies have been repeatedly showing significant efficacy of child car seats, if properly used, in preventing serious injuries and fatalities in young children during road accidents, due to restraining the children occupants against the ejection from the vehicle. Like many other developing countries, there is currently no legislation, in Pakistan, mandating the use of child car seats. Children exposure to traffic and risk of being involved in a traffic accident have been greatly increased in the country, over the past few years, due to increased number of vehicles, vehicle fleet, and trend of pre-schools and day care facilities. However, the awareness of parents regarding importance of safely traveling with infants and young children has not increased. Qualified and affluent parents have also been observed showing negligence in using the car child seats for their children. In this context, the objectives of this study were to investigate the level of awareness and usage of child car seats in Pakistan as well as to explore the need and interventions for conducting effective awareness campaigns or educational programs for parents in the country. Total 214 vehicles with children occupants and 385 children were observed at several schools, day-care centers, and pediatric departments in hospitals within 3 cities of Pakistan.@en

Introduction The objectives of this study were to investigate the level of awareness and usage of child car seats in Pakistan, identify problems that influence non-usage among the knowledgeable parents, as well as to explore the need and interventions for conducting effective awareness campaigns or educational programs for parents in the country. Methods Total 375 vehicles with children occupants and 622 children were observed at several schools, day-care centers, pediatric departments in hospitals, and children recreational places within 3 cities of Pakistan. Child safety restraints usage was almost negligible in the study sample. Out of the total 375 vehicles, 318 parents/drivers participated in the interview survey. Results Almost half of the participants were found to be unaware of child car safety restraints. Those who knew, most commonly expressed unavailability, time taken in child car seat installation, and absence of law as the reasons behind not using the child car seats while another common reason was their misperception about the children age group for using child car seats. Driver's education level was found to be the most significant (p < 0.0001) demographic characteristic associated with the driver's awareness on child car seats as well as support towards their usage, initiation of awareness campaigns, and law implementation. Conclusions The findings of the study indicate a great need and potential for child car seat educational programs as well as market for such devices especially among educated and affluent parents. The findings of the study also identify parents’ behaviors and attitudes, existing problems, and highlight several challenges and recommendations for planners, policy makers, transportation safety specialists, pediatricians, law enforcement agencies, as well as manufacturers for promoting children road safety.@en

Traffic signals at intersections located in closed proximity to a roadway-rail grade crossing often benefit from coordination with nearby railroad signals in order to alleviate both safety and operational issues associated with such locations. Analysis of traffic queues at these locations is of primary importance for determining if the normal signal operation needs to be preempted for railroad operations. Such queuing analysis becomes even more critical when direct observations of traffic queues are not possible or where the assessment is needed for a future location. Underestimation of queue lengths may lead to an unsafe design while significantly overestimated queues may cause unnecessary traffic delays consequently leading to violations of the active traffic control devices at the crossing. This research evaluated and compared commonly used micro-simulation models (i.e. Sim-Traffic and VISSIM) for their adequacy in estimating the queue spill-back lengths from traffic signals in the proximity of railroad crossings. Several additional comparisons were made between the queue estimation from the simulation-based and other deterministic analytical methods including Highway Capacity Software, Synchro, and a Railroad Assessment Tool that was developed as a part of this research. These comparisons helped identify the differences and specific limitations of each method in estimating adequate queue lengths. Recommendations were developed based on each model’s ability to capture the impact of various significant traffic factors on queue estimation, while minimizing the risk of underestimated queues.@en

The most critical concern with respect to the development of driverless vehicle technology is its safety and reliability. Inadequate technological advancements may lead to serious implications especially in terms of loss of human life. Moreover, technological advancements bring socio-technical complexities where the role of human, being the key element of a system, becomes highly important. Benefits of advanced technologies in driverless vehicles cannot be realized properly if safety related concerns have not been appropriately addressed in the design process. One possible way forward is to get feedback from the users of technology and incorporate design requirements accordingly. For acquiring the necessary information on various safety related issues that might be faced by the drivers, this public opinion based survey study has been conducted in China and Pakistan which mainly aims at capturing the public reliance level, perceptions and expectations on driverless vehicle system, more specifically on safety related issues. A web-based survey, containing some general questions about safety especially under some given driving scenarios, was launched in both the countries. The survey findings provide a useful insight for stakeholders towards user’s expectations, their safety perceptions and differences in the level of trust on modern vehicle technologies between the people of an emerging economy (China) and low-income country (Pakistan). The results also direct towards the need for further exploration of safety related concerns so that the issues could be addressed pragmatically during the design process.@en