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Abstract

Connected and automated vehicles (CAVs) are expected to enhance traffic efficiency by driving at shorter time headways, and traffic safety by shorter reaction times. However, one of the main concerns regarding their deployment is the mixed traffic situation, in which CAVs and manually driven vehicles (MVs) share the same road. This study investigates the behavioural adaptation of MV drivers in car-following and lane changing behaviour when they drive next to a dedicated lane (DL) for CAVs and compares that to a mixed traffic situation. The expectation is that in a mixed traffic situation, the behavioural adaptation of MV drivers is negligible due to lower exposure time and scarce platoons, while concentrating the CAVs on one dedicated lane may cause significant behavioural adaptation of MV drivers due to a higher exposure time and conspicuity of CAV platoons. Fifty-one participants were asked to drive an MV on a 3-lane motorway in three different traffic scenarios, in a fixed-base driving simulator: (1) Base, only MVs were present in traffic, (2) Mixed, platoons of 2–3 CAVs driving on any lane and mixed with MVs, (3) DL, platoons of 2–3 CAVs driving only on a DL. The DL was recognizable by road signs and a buffer demarcation which separated the DL from the other lanes. A moderate penetration rate of 43% was assumed for CAVs. During the drives, the car following headways and the accepted merging gaps by participants were collected and used for comparisons of driving behaviour in different scenarios. Based on the results, we conclude that there is no significant difference in the driving behaviour between Base and Mixed scenarios at tested penetration rate, confirming our research expectation. However, in DL scenario, MV drivers drove closer to their leaders specially when driving on the middle lane next to the platoons and accepted shorter gaps (up to 12.7% shorter at on-ramps) in lane changing manoeuvres. Dedicating a lane to CAVs increases the density of CAV platoons on one lane and consequently their conspicuity becomes higher. As a result, MV drivers are influenced by CAV platoons on a DL and imitate their behaviour. The literature suggests that dedicating a lane to CAVs improves the traffic efficiency by providing more possibilities for platooning. This study shows that implementing such a solution will affect the driving behaviour of human drivers. This should be taken into consideration when evaluating the impacts of dedicated lanes on traffic efficiency and traffic safety.

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... Each experiment is repeated 10 times with different seeds, the average 13 results are reported. 14 The mixed lane policy (for both lanes) for the entire simulation time is considered as the baseline 15 scenario, against which the other scenarios are compared. the second policy consists of a dynamic 16 dedicated lane policy in different AV rate levels, which is called DDL. 17 ...
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... This suggests drivers' intentions to exploit the technological advantages of AVs and the AVs' ability to perform safer maneuvers. Rad, Farah, Taale, van Arem, & Hoogendoorn, 2021 studied human drivers' behavior on motorways in three different scenarios in a driving simulator. In the first scenario, the human drivers interacted with platoons of 2-3 connected and automated vehicles that were mixed in traffic consisting as well of manually driven vehicles (called 'Mixed' scenario). ...
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This article deals with urban traffic speeds and pedestrian safety. According to a mathematical model, pedestrian safety depends to an alarming degree on vehicular speed: a speed of 50 km/h increases the risk of death almost eight-fold compared to a speed of 30 km/h. Video-taped records of real-life accidents are introduced as a new source of information. They show that the so-called 'free vehicles' and their speed determine the safety of pedestrians. Finally, the new 40 km/h speed limits in Helsinki's inner city are described and some initial observations concerning their effects on driving speeds are made.
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Abstract: Electronically coupled platoons of vehicles have the potential to increase the efficiency of transport on unmodified motorways. In doing so, the time headway (THW) between participating vehicles will be dramatically reduced. The present study investigated whether drivers are willing to keep a THW smaller than their preferred one to conform to the norm established by the presence of platoons holding short THWs. Firstly, two constructs had to be distinguished to answer this question: the preferred THWs represent a range of THWs drivers feel safe with and the THW that is indeed adopted by drivers in a given situation (adopted THW). Secondly, comparing adopted and preferred THW informs about whether drivers would adopt a THW beyond their preferred one as a result of the influence of platoons. Forty-two participants were asked to follow a lead vehicle (LV) in three different traffic conditions. In two conditions, there was a platoon of vehicles in the inside lane, where the THW between the vehicles was either large (THW = 1.0 s) or short (THW = 0.3 s). In a third baseline drive, the LV was the only vehicle present. Preferred THW was assessed after each traffic conditions with the psychophysical method of limits. Results show a consistency of preferred THW and there is a significant difference in adopted THW values throughout the conditions, which supports the idea of two distinct constructs. Further, participants’ minimum adopted THW did not drop under but was very close to the minimum preferred THW in condition THW03. It can be concluded that platoons could lead drivers to drive closer to their limits. Further studies need to investigate if in other conditions, drivers would go below their limit and in this case, consequences on the drivers (e.g. in terms of safety, workload and performance) will also require further investigations.
Article
Considerable research effort has been devoted within the past 15 years to automating the driving of highway vehicles in order to improve their safety and efficiency of operation and to help to reduce traffic congestion. Although the highway environment is in some ways more structured than other environments in which automated vehicles have been proposed to operate, the density and complexity of road traffic still make the sensing and control problems challenging. Because highway vehicles are not 'unmanned' but are expected to carry passengers and to coexist with other passenger-carrying vehicles, the reliability and safety considerations in the design of their control systems are much more important than they are for vehicles that are truly unmanned. This paper reviews the progress that has been made in recent research on highway vehicle automation and indicates the important research challenges that still need to be addressed before highway automation can become an everyday reality.
Article
Simulator sickness (SS) in high-fidelity visual simulators is a byproduct of modem simulation technology. Although it involves symptoms similar to those of motion-induced sickness (MS), SS tends to be less severe, to be of lower incidence, and to originate from elements of visual display and visuo-vestibular interaction atypical of conditions that induce MS. Most studies of SS to date index severity with some variant of the Pensacola Motion Sickness Questionnaire (MSQ). The MSQ has several deficiencies as an instrument for measuring SS. Some symptoms included in the scoring of MS are irrelevant for SS, and several are misleading. Also, the configural approach of the MSQ is not readily adaptable to computer administration and scoring. This article describes the development of a Simulator Sickness Questiomaire (SSQ), derived from the MSQ using a series of factor analyses, and illustrates its use in monitoring simulator performance with data from a computerized SSQ survey of 3,691 simulator hops. The database used for development included more than 1,100 MSQs, representing data from 10 Navy simulators. The SSQ provides straightforward computer or manual scoring, increased power to identify "problem" simulators, and improved diagnostic capability.
Article
The present paper describes a study that aims at assessment of driver behaviour in response to new technology, particularly Adaptive Cruise Control Systems (ACCs), as a function of driving style. In this study possible benefits and drawbacks of Adaptive Cruise Control Systems (ACCs) were assessed by having participants drive in a simulator. The four groups of participants taking part differed on reported driving styles concerning Speed (driving fast) and Focus (the ability to ignore distractions), and drove in ways which were consistent with these opinions. The results show behavioural adaptation with an ACC in terms of higher speed, smaller minimum time headway and larger brake force. Driving style group made little difference to these behavioural adaptations. Most drivers evaluated the ACC system very positively, but the undesirable behavioural adaptations observed should encourage caution about the potential safety of such systems.
Article
Constructing a valid measure of presence and discovering the factors that contribute to presence have been much sought after goals of presence researchers and at times have generated controversy among them. This paper describes the results of principal-components analyses of Presence Questionnaire (PQ) data from 325 participants following exposure to immersive virtual environments. The analyses suggest that a 4-factor model provides the best fit to our data. The factors are Involvement, Adaptation/Immersion, Sensory Fidelity, and Interface Quality. Except for the Adaptation/Immersion factor, these factors corresponded to those identified in a cluster analysis of data from an earlier version of the questionnaire. The existence of an Adaptation/Immersion factor leads us to postulate that immersion is greater for those individuals who rapidly and easily adapt to the virtual environment. The magnitudes of the correlations among the factors indicate moderately strong relationships among the 4 factors. Within these relationships, Sensory Fidelity items seem to be more closely related to Involvement, whereas Interface Quality items appear to be more closely related to Adaptation/Immersion, even though there is a moderately strong relationship between the Involvement and Adaptation/Immersion factors.
Article
This study was intended first to replicate, on two-lane highways, of the Evans and Wasielewski (Accident Analysis & Prevention 14, 57-64, 1982; 15, 121-136, 1983) results on the connection between close-following driving and traffic offenses and, second, to reveal reasons for close-following. A sample of close-following drivers (N = 157) and control drivers (N = 178) was picked from the flow on two-lane main highways. The driver records of the past 3 years showed retrospectively that the close-followers had accumulated 2.3 times more traffic offenses than had the control drivers and 2.0 times more when mileage was taken into account. The result is in agreement with the Evans and Wasielewski results for multi-lane highways, with the additional check for mileage in these data. However, the effect only occurred in males and was more marked in young males. Close-following females even indicated a tendency of having fewer offenses than their controls when their higher mileage was taken into account. Another sample of close-followers interviewed on the road revealed that hurry or desire to overtake the car ahead was the justification for the close-following in the majority of cases. It was suggested that on two-lane highways close-following substantially stems from overtaking needs and maneuvering connected to higher target speeds. This study partly confirms the connection between close-following and an increased number of offenses in comparisons between drivers. However, the suggested connection between close-following and accident involvement, as based on interindividual comparisons, still remains somewhat open.
Article
Two studies were conducted in order to develop a multidimensional instrument of driving style. In Study 1, we developed a self-report scale assessing four broad domains of driving style-the multidimensional driving style inventory (MDSI). A factor analysis revealed eight main factors, each one representing a specific driving style--dissociative, anxious, risky, angry, high-velocity, distress reduction, patient, and careful. In addition, significant associations were found between the eight factors, on the one hand, and gender, age, driving history, and personality measures of self-esteem, need for control, impulsive sensation seeking, and extraversion, on the other. In Study 2, further associations were found between the eight driving style factors and measures of trait anxiety and neuroticism. The discussion focused on the validity and utility of a multidimensional conceptualization of driving style.
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Implications of Connected and Automated Vehicles on the Safety and Operations of Roadway Networks: A Final Report Implications of Connected and Automated Vehicles on the Safety and Operations of Roadway Networks: A Final Report
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Road Transport Automation Road Map and Action Plan
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Taxonomy and Definitions for Terms Related to Driving Automation Systems for On-Road Motor Vehicles
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SAE. (2018). Taxonomy and Definitions for Terms Related to Driving Automation Systems for On-Road Motor Vehicles. Retrieved from https://www.sae.org/ standards/content/j3016_201806/ https://www.sae.org/standards/content/j3016_201806/.