Image Characteristics and Their Effect on Driving Simulator Validity

Due to financial and computational limitations, the image quality presented in driving simulators is often a trade-off between resolution, pixel density and field of view. The current study examined this trade-off by investigating the effect of image resolution and horizontal field of view on the validity of the Leeds Driving Simulator. There were three levels of pixel density: low (3.6 arc min per pixel), high (2.6 arc min per pixel) and real world, and four levels of field of view: narrow (50°), medium (120°), wide (230°) and real world. Results seemed to show that widening the field of view improved the validity of speed choice and lane position between simulated and real world driving conditions, whilst there was no significant effect of image resolution

The Effectiveness of Safety Campaign VMS Messages - A Driving Simulator Investigation

This report outlines an off-road trial of the effectiveness of Safety Campaign Messages (such as “Watch Your Speed”) sometimes displayed on Variable Message Signs (VMS) throughout the U.K.’s motorway network. Eighty drivers took part in the driving simulator study. It primarily investigated the effectiveness of the individual messages and how their presence affected driver behaviour towards more critical Tactical Incident Messages (TIM), such as those that might warn of an impending hazard. Both the content and concentration of the Safety Campaign Messages were varied. The Safety Campaign Messages in themselves were not especially beneficial, in that drivers did not significantly modify their driving style purely on the advice of the messages. However, witnessing the odd VMS carrying such a message appeared to improve driver alertness to the context of the VMS and consequently response to a TIM became more timely under these conditions. Yet, if the frequency of Safety Campaign Messages was overly high, drivers became jaded with the VMS content and their ability to act appropriately to a TIM degraded

A Driving Simulator Study to Examine the Role of Vehicle Acoustics on Drivers’ Speed Perception

In recent years, there has been a desire by vehicle manufacturers to reduce the in-cab noise of vehicles, in order to improve driver comfort and enhance the enjoyment of in-vehicle entertainment systems. This reduction of incab noise is accompanied by policy initiatives to reduce transport related noise by implementing low noise road surfaces. However, it is not known how such reductions in the availability of auditory cues affect drivers’ ability to judge speed, and there is a danger that drivers will increase their speed, to compensate for the absence of auditory cues. In this study, drivers were required to maintain speed at 30 and 70 mph, in the absence of a speedometer, with and without accompanying vehicle noise. Results showed that drivers’ ability to maintain the correct speed profile was much more variable in the absence of accompanying vehicle noise and this variation was found to be higher when drivers were asked to travel at higher speeds of 70 mph. Drivers were also found to travel faster than the required speed in the absence of vehicle noise, although their ability to maintain speed was generally worse at 70 mph, even in the presence of auditory cues

Motion cueing in driving simulators for research applications

This research investigated the perception of self-motion in driving simulation, focussing on the dynamic cues produced by a motion platform. The study was undertaken in three stages, evaluating various motion cueing techniques based on both subjective ratings of realism and objective measures of driver performance. Using a Just Noticeable Difference methodology, Stage 1 determined the maximum perceptible motion scaling for platform movement in both translation and tilt. Motion cues scaled by 90% or more could not be perceptibly differentiated from unscaled motion. This result was used in Stage 2‟s examination of the most appropriate point in space at which the platform translations and rotations should be centred (Motion Reference Point, MRP). Participants undertook two tracking tasks requiring both longitudinal (braking) and lateral (steering) vehicle control. Whilst drivers appeared unable to perceive a change in MRP from head level to a point 1.1m lower, the higher position (closer to the vestibular organs) did result in marginally smoother braking, corresponding to the given requirements of the longitudinal driving task. Stage 3 explored the perceptual trade-off between the specific force error and tilt rate error generated by the platform. Three independent experimental factors were manipulated: motion scale-factor, platform tilt rate and additional platform displacement afforded by a XY-table. For the longitudinal task, slow tilt that remained sub-threshold was perceived as the most realistic, especially when supplemented by the extra surge of the XY-table. However, braking task performance was superior when a more rapid tilt was experienced. For the lateral task, perceived realism was enhanced when motion cues were scaled by 50%, particularly with added XY-sway. This preference was also supported by improvements in task accuracy. Participants ratings were unmoved by changing tilt rate, although rapid tilt did result in more precise lane control. Several interactions were also observed, most notably between platform tilt rate and XY-table availability. When the XY-table was operational, driving task performance varied little between sub-threshold and more rapid tilt. However, while the XY-table was inactive, both driving tasks were better achieved in conditions of high tilt rate. An interpretation of these results suggests that without the benefit of significant extra translational capability, priority should be given to the minimisation of specific force error through motion cues presented at a perceptibly high tilt rate. However, XY-table availability affords the simulator engineer the luxury of attaining a slower tilt that provides both accurate driving task performance and accomplishes maximum perceived realism

Bilingual Variable Message Signs: A Study of Information Presentation and Driver Distraction

Research on static bilingual signs has confirmed increasedreading times compared to their monolingual counterparts; however there islittle empirical research on bilingual Variable Message Signs (VMS). Thestudy reported here evaluates the effect of various bilingual VMSconfigurations on driver behaviour and safety. The aim of the study was todetermine whether or not the visual distraction associated with bilingualVMS signs of different configurations (length, complexity) impacted ondriving performance. The results suggest that four-line bilingual VMS signscomprising 2 lines of text in each language are read by both monolingualand bilingual drivers in a manner that more closely approximates a two-linemonolingual sign. This being the case it is likely that the deployment offour-line bilingual signs on Welsh motorways is unlikely to result in asignificant reduction in safety

Can Low Cost Road Engineering Measures Combat Driver Fatigue? A Driving Simulator Investigation

Driver fatigue is a major cause of road accidents, accounting for over 20% of serious accidents on motorways and monotonous roads in the U.K. This study investigated the potential for low-cost, road-based, engineering measures to act as alerting features in an otherwise monotonous driving environment and hence combat fatigue. Thirty-three drivers took part in the driving simulator study. There was some evidence of an alerting effect provided to drivers by all three of the treatments tested: chevron road-surface markings, transversecarriageway rumble strips and variable message signs. However, the alerting effect did appear to be relatively weak and potentially quite short-lived. Nevertheless, there may well be potential for any of the novel alerts to be deployed in the field in a known fatigue-related accident area

Shut up I\u27m Driving! Is Talking to an Inconsiderate Passenger the Same as Talking on a Mobile Telephone?

The objective of this study was to compare driving performance whilst talking on a hands-free mobile (cellular) telephone with performance during conversations with “considerate” and “inconsiderate” passengers. Using the Leeds Advanced Driving Simulator, participants were asked to drive through a road containing four driving scenarios: (1) car following along a straight road section, (2) car following along a curved section of road, (3) a braking event, and (4) a coherence event. A working memory digit recall and sentence verification task were used to simulate conversation in three conversation conditions: (1) “considerate passenger,” where the experimenter asked drivers to responsd to the working memory task before and after a driving event, (2) “inconsiderate passenger,” where the experimenter asked drivers to responsd to the working memory task throughout a driving event, and “3) “mobile phone task,” which involved digital presentation of the working memory task via a mobile telephone throughout the driving events. A silent condition was also used as control. The effect of the three conversation conditions on driving performance was the same during the simple car following scenarios. However, talking to an “inconsiderate” passenger was found to be as disrupting as a mobile phone conversation, and different from conversing with a considerate passenger, during the braking and coherence conditions. Therefore, the high workload imposed by conversation was only detrimental during the more difficult driving conditions, when demand for central attentional resources from both tasks was at its highest

Multisensory Signal Detection: How Does Driving and IVIS Management Affect Performance?

Signal detection was used as a ‘tertiary’ task to assess drivers’ ‘spare processing capacity’ during the performance of two in-vehicle information systems (IVIS). The main aims of the study were: a) to establish if performance on signal detection can be used to assess IVIS safety during driving and b) to determine whether signal modality is important for this assessment. Participants performed each IVIS (Phone or Count) during a driving simulation experiment. In addition to performing the driving and IVIS, participants were required to complete three detection tasks (DT): (i) a visual DT (ii) an auditory DT, and (iii) a tactile DT. Average reaction time to the DTs was found to increase by around 200ms when performed with the IVIS tasks. It can be argued that any significant increase in reaction time to the DTs is a good indicator of drivers’ reduced hazard perception/situation awareness, which might occur as a result of using in-car systems. No significant difference in performance was found between the various DTs, suggesting that performance relies on central attentional resources, and is not modality-specific. This affords some flexibility for assessing the safety of IVIS in different driving environments. For instance, an auditory DT might be used in field studies on a sunny day when bright light hinders detection of LEDs used in a visual version of the task. Similarly, the tactile version of the task might be useful for testing IVIS in a noisy driving environment

The Design of Haptic Gas Pedal Feedback to Support Eco-Driving

Previous literature suggests that haptic gas pedals can assist the driver in search of maximum fuel economy. This study investigated three haptic pedal designs, each with high and low intensities of feedback, in a rapid prototyping, paired comparison design. Twenty drivers took part, experiencing the systems in a high-fidelity driving simulator. Results suggested that drivers were best guided towards an “idealized” (most fuel efficient) gas pedal position by force feedback (where a driver feels a step change in gas pedal force) as opposed to stiffness feedback (where a driver feels a changing gas pedal firmness). In either case, high levels of force/stiffness feedback were preferred. Objective performance measures mirrored the subjective results. Whilst the short-term nature (brief system exposure) of this study led to difficulties in drawing longer-term conclusions, it would appear that force feedback haptics are better suited than stiffness feedback to augment an effective driver interface supporting “green” driving

Fully-Automated Driving: The Road to Future Vehicles

The study investigated the impact of fully-automated vehicle control on driver behaviour, physiology and the uptake of secondary tasks in varying traffic conditions. Previous studies have indicated the potential ironies of such automation on fatigue, stress and situational awareness, but have also suggested potential benefits through enhanced safety, more efficient traffic flows and reduced driver workload. The research was undertaken in a high-fidelity driving simulator that allowed drivers to see, feel and hear the impact of the automated control. Independent factors of Drive Type (manual control, fully-automated) and Traffic Density (light, heavy) were manipulated in a repeated-measures experimental design. 49 drivers participated. Drivers experiencing full vehicle automation tended to refrain from behaviours, such as overtaking, that required them to temporarily retake manual control, accepting the resulting increase in journey time. Automation improved safety margins in car following, but this benefit was restricted only to conditions of light surrounding traffic. Automation also reduced heart rate and increased driver fatigue, the latter being mitigated somewhat by high traffic density. Furthermore, drivers became more heavily involved with in-vehicle entertainment than they were in manual driving, affording less visual attention to the road ahead. Drivers do appear happy to forgo their supervisory responsibilities in preference of a more entertaining automated drive. However, these responsibilities are taken more seriously as supervisory demand increases