Evaluation of techniques to improve the legibility of bilingual Variable Message Signs

This study evaluated a number of techniques that could be employed to reduce the amount of time drivers spend searching and reading bilingual signs. Using a tachistoscope, monolingual and Welsh bilingual participants were presented with various configurations of bilingual signing. The amount of information was varied (i.e. the number of lines) and a number of language-differentiation techniques were implemented. These techniques attempted to aid the perception and recognition of the relevant language and relied either on manipulating the position of the two languages, or by using demarcation (colour, font etc.). With regards to the amount of information presented, it was found that the reading response time for a single line of relevant text within a two-line bilingual sign was not significantly different to the reading response time for a one-line monolingual sign. Thus, participants were able to extract the relevant language from the bilingual sign with no decrement in performance. However, reading response time for a message of two lines of relevant text in a four-line bilingual was significantly longer than the reading response time for a two-line monolingual sign. Thus the amount of information (even if irrelevant) impacted on their performance. With regards to the positioning techniques, grouping the lines by language resulted in a decreased reading response time compared to when the text was grouped by content. In addition, positioning the user’s dominant language at the top of the sign improved reading times for both one and two-line messages on bilingual signs. All the demarcation techniques were successful in reducing reading times on four-line bilingual signs, and it was found that having established a particular pattern of presentation, an unexpected change significantly increased reading time

Safety implications of a pedestrian protection system - the driver's point of view

Pedestrians can sustain fatal injuries, even in low-speed collisions. Active pedestrian protection systems, such as an Active Bonnet, have been shown to mitigate the outcome of a collision. The study reported here aimed to discover whether such a system could have any negative impacts on the driver. One of the characteristics of the Active Bonnet is that, when deployed, it partially occludes the driver’s visual field. This driving simulator study quantified the amount of disruption to normal driving when the system is deployed, for drivers of three different heights. Curved and straight sections of road were simulated and occlusion time varied between 0.5 seconds and 4 seconds. In general, drivers’ reaction to the deployment of the bonnet was to decrease their speed; this was most noticeable for drivers at the lowest eye-height both in the straight and curved sections of road. On straight sections of road, drivers were able to maintain vehicle speed and lateral control for up to three seconds of partial occlusion of the visual field. For curved sections, this upper threshold was found to be only two seconds, reflecting the higher workload in the curved sections. When occlusion was lifted, drivers tended to then deviate in lane – a possible “panic” effect. As drivers became more familiar with the system, they applied the brakes less. In conclusion, according to the scenarios tested in this study, drivers appear to be able to cope with partial occlusions of two seconds or less and there is some evidence that a panic reaction can be lessened by familiarisation

The design of an in-vehicle assistance system to support eco-driving

This driving simulator study was the second of two studies investigating the most effective and acceptable in-vehicle system for the provision of guidance on fuel efficient accelerator usage. Three eco-driving interfaces were selected for test (a second-order display visual display with auditory alerts and two haptic accelerator pedal systems) following a pilot study of 12 different interfaces. These systems were tested in a range of eco-driving scenarios involving acceleration, deceleration and speed maintenance, and assessed through their effects on fuel economy, vehicle control, distraction, and driver subjective feedback. The results suggest that a haptic accelerator pedal system is most effective for preventing over-acceleration, while minimal differences were observed between systems in terms of the effect of the assistance provided to prevent under-acceleration. The visual-auditory interface lowered the time spent looking towards the road, indicating a potential negative impact on driver safety from using this modality to provide continuous green driving support. Subjective results were consistent with the objective findings, with haptic pedal systems creating lower perceived workload than a visual-auditory interface. Driver acceptability ratings suggested a slight favouring of a haptic-force system for its usefulness, whereas the more subtle haptic-stiffness system was judged more acceptable to use. These findings offer suggestions for the design of a user-friendly, eco-driving device that can help drivers improve their fuel economy, specifically through the provision of real-time guidance on the manipulation of the accelerator pedal position