A human factors perspective on automated driving Kyriakidis, M.; de Winter, J. C. F.; Stanton, N. ...
Theoretical issues in ergonomics science,
05/2019, Letnik:
20, Številka:
3
Journal Article
Recenzirano
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Automated driving can fundamentally change road transportation and improve quality of life. However, at present, the role of humans in automated vehicles (AVs) is not clearly established. Interviews ...were conducted in April and May 2015 with 12 expert researchers in the field of human factors (HFs) of automated driving to identify commonalities and distinctive perspectives regarding HF challenges in the development of AVs. The experts indicated that an AV up to SAE Level 4 should inform its driver about the AV's capabilities and operational status, and ensure safety while changing between automated and manual modes. HF research should particularly address interactions between AVs, human drivers and vulnerable road users. Additionally, driver-training programmes may have to be modified to ensure that humans are capable of using AVs. Finally, a reflection on the interviews is provided, showing discordance between the interviewees' statements - which appear to be in line with a long history of HFs research - and the rapid development of automation technology. We expect our perspective to be instrumental for stakeholders involved in AV development and instructive to other parties.
Robust public transport networks are important, since disruptions decrease the public transport accessibility of areas. Despite this importance, the full passenger impacts of public transport network ...vulnerability have not yet been considered in science and practice. We have developed a methodology to identify the most vulnerable links in the total, multi-level public transport network and to quantify the societal costs of link vulnerability for these identified links. Contrary to traditional single-level network approaches, we consider the integrated, total multi-level PT network in the identification and quantification of link vulnerability, including PT services on other network levels which remain available once a disturbance occurs. We also incorporate both exposure to large, non-recurrent disturbances and the impacts of these disturbances explicitly when identifying and quantifying link vulnerability. This results in complete and realistic insights into the negative accessibility impacts of disturbances. Our methodology is applied to a case study in the Netherlands, using a dataset containing 2.5 years of disturbance information. Our results show that especially crowded links of the light rail/metro network are vulnerable, due to the combination of relatively high disruption exposure and relatively high passenger flows. The proposed methodology allows quantification of robustness benefits of measures, in addition to the costs of these measures. Showing the value of robustness, our work can support and rationalize the decision-making process of public transport operators and authorities regarding the implementation of robustness measures.
•Interactions with driver and automated vehicles involve new types of complex behavioural processes.•Modelling these processes requires explicit inclusion of human factors in simulation.•An extended ...modelling framework is presented for mixed traffic that includes these behavioural interactions.•This novel approach explicitly considers driver cognitive loading and related performance with automated vehicles.•Two experimental cases, considering transition of control, demonstrate the face validity of the approach.
With an increasing number of automated vehicles (AV) appearing on roads and interacting with conventional traffic, there is a need for improved simulation approaches to replicate and forecast the resulting effects. Interactions between AVs and their drivers, and interaction with other human drivers involve new types of complex behavioural processes. There is an increasing necessity to explicitly incorporate these human factor processes in simulation, which cannot be properly accounted for with most current models. In this paper, we present an extended conceptual simulation framework based on human factors processes and applicable for automated driving that does this. The framework makes use of previously constructed constructs to include the effects of driver task demand, situation awareness and fundamental diagrams of task demand to extend to automated driving. This is especially considered for the case of transition of control (ToC), as an important aspect of vehicle-driver interaction. The framework is demonstrated in two experimental cases that consider different ToC situations and is found to be face valid within the applied assumptions. Challenges remain in regard to a lack of quantitative evidence from traffic psychology, automated vehicle dynamics & control and human-vehicle interaction. With increasing amounts of research on-going in these areas, the extended framework will act as a valuable approach to further study and quantify the effects of AVs in mixed traffic in the future.
•Truck platooning is near practice ready, but the effects on traffic flow remain unclear.•Traffic simulation extensions are proposed to model truck platoon interactions.•A case showed the effects on ...flow, merging at ramps and platooning ability.•Traffic flow is negatively affected by truck platooning, especially in saturated states.•Merging is affected, but not too detrimentally for short platoon sizes.
With automated and cooperative driving making its breakthrough, and related systems in fast development, their future influence and impact on roads and traffic may be extensive. Truck platooning is such an application that relies on the development of Cooperative Adaptive Cruise Control (CACC) and is said to be practice ready. While the main advantages of truck platooning lie in emission and energy reduction, claims are also being made for the influence on traffic flow. In this paper, we pose hypotheses based on some of the main claims. We also attempt to substantiate and give quantitative proof of the potential effects of truck platooning on traffic flow performance. The simulation model LMRS-IDM+ is extended to encompass the main influencing dynamics related to potential effects of truck platooning, based on empirical findings. The effects of truck platooning were tested for the influence of traffic states, truck gap settings, platoon sizes, and the share of equipped trucks. This resulted in outcomes regarding the total traffic performance, the performance of traffic at ramps, and the ability of a platoon to remain platooning as part of a case experiment performed on a part of the Trans-European ITS Corridor. The results showed that truck platooning may have a small negative effect on the total non-saturated traffic flow, however with a much larger negative effect on saturated traffic flow. However, drivers may be reluctant to platoon in saturated traffic in any case. The ability of inflowing traffic to merge at on-ramps was found to be affected by truck platoons, with platoon disengagements occurring under various conditions. The applied gap settings for platooning trucks did not significantly affect the merge time, while a higher gap did lead to a higher number of disengagements. The ability of trucks to platoon was positively affected by a greater percentage of equipped trucks and by larger platoon sizes. Shorter gap times also slightly improved the ability of trucks to remain in platooning formation. Finally, recommendations are given to improve platoon strategies and for policymakers to only allow truck platooning outside of busy (near-) saturated traffic, even though drivers may be reluctant to use the system in these conditions. Also, recommendations are made to investigate potential differences in the effects between the European and American contexts for truck-platooning.
Cooperative adaptive cruise control (CACC) is an extension of ACC. In addition to measuring the distance to a predecessor, a vehicle can also exchange information with a predecessor by wireless ...communication. This enables a vehicle to follow its predecessor at a closer distance under tighter control. This paper focuses on the impact of CACC on traffic-flow characteristics. It uses the traffic-flow simulation model MIXIC that was specially designed to study the impact of intelligent vehicles on traffic flow. The authors study the impacts of CACC for a highway-merging scenario from four to three lanes. The results show an improvement of traffic-flow stability and a slight increase in traffic-flow efficiency compared with the merging scenario without equipped vehicles
A novel strategy to enhance string stability of autonomous vehicles with sensor delay and actuator lag is proposed based on a model predictive control framework. To compensate sensor delay, the ...approach entails estimating the (unknown) system state at the current time using the system state in a previous time, the applied control history and a system dynamics model. The actuator lag is compensated by including the lag in the state prediction model. The mathematical framework shows that without the anticipation strategy, sensor delay leads to a worse estimate of the initial condition for the optimal control problem and actuator lag increases the mismatch between the system state prediction model and the actual system behaviour. Simulation verified that sensor delay and actuator lag degrade string stability of platoons. The proposed anticipatory control strategy shows clear benefits in improving autonomous vehicle string stability and hence has potential to enhance traffic flow stability.
Modern cars are increasingly being equipped with automated driving functions. For governments it is important to gain insight in the mobility impacts of automated vehicles. This is important as the ...introduction of automated vehicles affects current investment decisions about infrastructure projects and other policy measures like road pricing. Quantitative literature with respect to the impact of automated vehicles focuses mostly on capacity implications. Literature about large scale mobility impacts is mainly qualitative. This paper introduces a System Dynamics model (SD-model) to quantitatively explore the impacts of early forms of automated vehicles (level 1, 2 and 3) on mobility. The model is explorative and can be used to evaluate different scenarios in a short time. This model is applied in a case study for the Netherlands to assess the impact of automated vehicles on mode choice, time of day choice and travel times on characteristic relations in the Netherlands. In contrast to other studies the SD-model is able to simulate the effects of AVs over time, can simulate mixed automated vehicle types and has a constant feedback between the assignment and the demand side of the model. A scenario for autonomous driving and a scenario for cooperative driving is considered. The simulations show that car traffic will increase and the level of congestion does not necessarily decrease and might even increase on some relations, especially in the autonomous scenario. Furthermore, in the cooperative scenario the increase in number of trips by car is larger, the average speeds are higher and there is less congestion compared to the autonomous scenario.
•Explorative model which gives insight in the largest uncertainties of the mobility impacts of automated vehicles.•A method to simulate effects of automated vehicles in macroscopic models.•Year-to-year simulation with increasing penetration rates of automated vehicles.•Uncertainties considered with respect to penetration rates, impact on capacity and impact on value of time.•A case study for the Netherlands.
E-commerce is still a strong growing segment with fierce competition among parcel delivery service providers. To stay ahead of the competitors innovation is necessary. Currently, parcels are being ...delivered with large delivery vans which will usually deliver single parcels to doorsteps of their customers. This so called ‘last mile delivery’ is the most expensive logistics activity. In the literature it is proposed that parcel lockers have high potential to save cost. In our paper a literature review on parcel lockers, 3 methods for analysis are described and the results of a case study are provided.
•Microscopic model with lane change and car-following for CACC.•Representation of operational design domain and authority transition.•New insights into capacity and flow heterogeneity of CACC ...traffic.•Strong correlation between congestion and authority transition.
Cooperative Adaptive Cruise Control (CACC) systems have the potential to increase roadway capacity and mitigate traffic congestion thanks to the short following distance enabled by inter-vehicle communication. However, due to limitations in acceleration and deceleration capabilities of CACC systems, deactivation and switch to ACC or human-driven mode will take place when conditions are outside the operational design domain. Given the lack of elaborate models on this interaction, existing CACC traffic flow models have not yet been able to reproduce realistic CACC vehicle behaviour and pay little attention to the influence of system deactivation on traffic flow at bottlenecks. This study aims to gain insights into the influence of CACC on highway operations at merging bottlenecks by using a realistic CACC model that captures driver-system interactions and string length limits. We conduct systematic traffic simulations for various CACC market penetration rates (MPR) to derive free-flow capacity and queue discharge rate of the merging section and compare these to the capacity of a homogeneous pipeline section. The results show that an increased CACC MPR can indeed increase the roadway capacity. However, the resulting capacity in the merging bottleneck is much lower than the pipeline capacity and capacity drop persists in bottleneck scenarios at all CACC MPR levels. It is also found that CACC increases flow heterogeneity due to the switch among different operation modes. A microscopic investigation of the CACC operational mode and trajectories reveals a close relation between CACC deactivation, traffic congestion and flow heterogeneity.
Delays Caused by Incidents Snelder, M.; Bakri, T.; van Arem, B.
Transportation research record,
01/2013, Letnik:
2333, Številka:
1
Journal Article
Recenzirano
Road networks are becoming more vulnerable to incidents as a result of the increasing level of congestion. An innovative empirical method is proposed and applied to analyze the delays caused by about ...490,000 incidents that occurred in the Netherlands in the period 2007 to 2009. The method was applied to the motorway network of the Netherlands for which detailed loop detector data were available and for which incidents were registered. The method contributes to the existing literature by explaining how delays that are caused by incidents can be computed by selecting a reference day and by tracing the effects of incidents. The method considers upstream delays on the road where the incident occurred, spillback effects to other roads, and rubbernecking effects. The method provides insight for the locations that are most vulnerable to incidents and a basis for taking robustness measures and understanding the potential benefits of these measures.
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