Investigating Initial Driver Intention on Overtaking on Rural Roads

Driver intention recognition is essential to the development of advanced driver assistance systems providing real-time support. Current approaches for the recognition of overtaking intentions focus on drivers’ observable behaviors, neglecting the fact that the intention to overtake a slower lead car emerges earlier than the resulting behavior. This paper aims to distinguish the "intention emerging process", when drivers form the initial intention to overtake, from the "action executing process", when drivers execute the overtaking maneuver. A driving simulator study has been conducted to investigate the influence of the lead vehicle type and lead vehicle speed on initiating driver’ intention on overtaking on rural roads, and the effect of the complexity of the oncoming traffic on executing overtaking. The results show that the initial driver intention to overtake appears much earlier than the execution of the overtaking maneuver. The lead vehicle speed has a significant influence on initial driver intention in the "intention emerging process", while time to overtake increases with the number of the oncoming vehicles in the "action execution process". These results can contribute to the development of models for driver intention recognition by extending the prediction horizon from the recognition to a prediction of driving maneuvers. Document type: Conference objec

Driven to distraction: Determining the effects of roadside advertising on driver attention

There is growing concern that roadside advertising presents a real risk to driving safety, with conservative estimates putting external distractors responsible for up to 10% of all accidents. In this report, we present a simulator study quantifying the effects of billboards on driver attention, mental workload and performance in Urban, Motorway and Rural environments. The results demonstrate that roadside advertising has a clear detrimental effect on lateral control, increases mental workload and eye fixations, and on some roads can draw attention away from more relevant road signage. Detailed analysis of the data suggests that the effects of billboards may in fact be more consequential in scenarios which are monotonous or of lower workload. Nevertheless, the overriding conclusion is that prudence should be exercised when authorising or placing roadside advertising. The findings are discussed with respect to governmental policy and guidelines.Final report of a study funded by The Rees Jeffreys Road Fun

Identification of road user related risk factors, deliverable 4.1 of the H2020 project SafetyCube.

Safety CaUsation, Benefits and Efficiency (SafetyCube) is a European Commission supported Horizon 2020 project with the objective of developing an innovative road safety Decision Support System (DSS). The DSS will enable policy-makers and stakeholders to select and implement the most appropriate strategies, measures, and cost-effective approaches to reduce casualties of all road user types and all severities. This document is the first deliverable (4.1) of work package 4 which is dedicated to identifying and assessing human related risk factors and corresponding countermeasures as well as their effect on road safety. The focus of deliverable 4.1 is on identification and assessment of risk factors and describes the corresponding operational procedure and corresponding outcomes. The following steps have been carried out: Identification of human related risk factors – creation of a taxonomy Consultation of relevant stakeholders and policy papers for identification of topic with high priority (‘hot topics’) Systematic literature search and selection of relevant studies on identified risk factors •Coding of studies •Analysis of risk factors on basis of coded studies •Synopses of risk factors, including accident scenarios The core output of this task are synopses of risk factors which will be available through the DSS. Within the synopses, each risk factor was analysed systematically on basis of scientific studies and is further assigned to one of four levels of risk (marked with a colour code). Essential information of the more than 180 included studies were coded and will also be available in the database of the DSS. Furthermore, the synopses contain theoretical background on the risk factor and are prepared in different sections with different levels of detail for an academic as well as a non-academic audience. These sections are readable independently. It is important to note that the relationship between road safety and road user related risk factors is a difficult task. For some risk factors the available studies focused more on conditions of the behaviour (in which situations the behaviour is shown or which groups are more likely to show this behaviour) rather than the risk factor itself. Therefore, it cannot be concluded that those risk factors that have not often been studied or have to rely more indirect and arguably weaker methodologies, e.g. self-reports , do not increase the chance of a crash occurring. The following analysed risk factors were assessed as ‘risky’, ‘probably risky’ or ‘unclear’. No risk factors were identified as ‘probably not risky’. Risky Probably risky Unclear • Influenced driving – alcohol • Influenced Driving – drugs (legal & illegal) • Speeding and inappropriate speed • Traffic rule violations – red light running • Distraction – cell phone use (hand held) • Distraction – cell phone use (hands free) • Distraction – cell phone use (texting) • Fatigue – sleep disorders – sleep apnea • Risk taking – overtaking • Risk taking – close following behaviour • Insufficient knowledge and skills • Functional impairment – cognitive impairment • Functional impairment – vision loss • Diseases and disorders – diabetes • Personal factors – sensation seeking • Personal factors – ADHD • Emotions – anger, aggression • Fatigue – Not enough sleep/driving while tired • Distraction – conversation with passengers • Distraction – outside of vehicle • Distraction – cognitive overload and inattention • Functional impairment – hearing loss (few studies) • Observation errors (few studies) • Distraction – music – entertainment systems (many studies, mixed results) • Distraction – operating devices (many studies, mixed results) The next step in SafetyCube’s WP4 is to identify and assess the effectiveness of measures and to establish a link to the identified risk factors. The work of this first task indicates a set of risk factors that should be centre of attention when identifying corresponding road safety measures (category ‘risky’)

Accident causation and pre-accidental driving situations: Part 1. Overview and general statistics

WP2 of the European Project TRACE is concerned with “Types of Situations” to analyse the causation of road traffic accidents from the pre-accidental driving situation point of view. Four complementary situations were defined: stabilized situations, intersection, specific manoeuvre and degradation scenario. To reach this objective, the analysis is based on a common methodology composed on 3 steps: the “descriptive analysis” which from general statistics will allow to identify among the studied situations those them relevant and to give their characteristics, the “in-depth analysis” allowing to obtain accident causes from the generic description of the problems identified in the previous step and the risk analysis identifying the risk of being involved in an accident taking into account the results obtained from the ‘in–depth’ level. This report is dedicated to the descriptive analysis with the identification of the most relevant scenario regarding the situation in which the driver is involved just prior the accident. The results are based on the literature review, general statistics and the analysis of the national databases available in TRACE via WP8. Because the information level differ from databases to another, the available scenario presented here for the 4 predefined types of situations are generics and some specific situations could not have be distinguished. For each situation some key indicators are given, such as prevalence, severity, KSI (killed x severely injured), etc. When it is possible, these indicators are estimated at the EU27 level

Understanding interactions between autonomous vehicles and other road users: A literature review

This review draws on literature relating to the interactions of vehicles with other vehicles, interactions between vehicles and infrastructure, and interactions between autonomous vehicles and cyclists and autonomous vehicles and pedestrians. The available literature relating to autonomous vehicles interactions is currently limited and hence the review has considered issues which will be relevant to autonomous vehicles from reading and evaluating a broader but still relevant literature.The project is concerned primarily with autonomous vehicles within the urban environment and hence the greatest consideration has been given to interactions on typical urban roads, with specific consideration also being given to shared space. The central questions in relation to autonomous vehicles and other road users revolve around gap acceptance, overtaking behaviour, behaviour at road narrowings, the ability to detect and avoid cyclists taking paths through a junction which conflict with the autonomous vehicle’s path, and the ability of autonomous vehicles to sense and respond to human gestures. A long list of potential research questions has been developed, many of which are not realistically answerable by the Venturer project. However, the important research questions which might potentially be answered by the current project are offered as the basis for the more detailed consideration of the conduct of the interaction trial

Rigid central safety barriers in constrained road environment

Road crashes are a continuing source of personal grief and economic loss in most societies. In NSW between October 2008 and September 2013, head-on crashes made up 5.5% of all rural road rashes in NSW but contributed to 27% of all fatalities on those roads. Head-on crashes tend to be concentrated at sites of substandard horizontal road geometry. Often, rectification of site geometry on constrained rural roads is beyond the limitations of Road Authorities. Installation of central barriers in narrow medians is a cost effective incremental solution but often comes at a sacrifice – reduction of sight distance, reduced recovery area and surface drainage implications. This study assesses the implication of introducing a concrete central safety barrier (CCSB) into an already substandard, complex road environment by assessing the before-and-after performance of nine concrete central safety barrier sites. The literature review compared the different types of central safety barriers including concrete (cast in-situ and pre-cast), guardrail and wire rope. When compared to wire rope and guardrail, concrete barriers are more suited to highly constrained road environments, having negligible deflection, being suitable for horizontal radius less than 200m and remaining operational post collision (reduced maintenance and worker exposure). The compromise with the system is increased crash severity, highest potential implications on surface drainage and sight. Although the severity index of concrete barriers is seemingly the highest of all barrier systems, the results typically agreed with general performance of all barriers: non-injury (tow-away) crashes increase in place of injury crashes and injury crashes increase in place of fatal crashes. Fatal crashes were almost entirely eliminated. CCSB were found to be an effective solution at eliminating head-on crashes at all nine sites investigated. The installation also had an improvement of general road safety at seven of the nine sites analysed. It is believed that the poor performance of the two remaining sites was likely attributed to poor co-ordination of horizontal and vertical geometry at one site and worsening of surface drainage conditions at the other. The total average reduction in fatalities across all sites was 111% and factored severity costs in all accidents reduced by 200%. Six of the nine sites had pre-cast concrete central barrier systems. Currently there is no current acceptance for the use of precast concrete barriers as a permanent installation. All six pre-cast sites had an overall positive impact on road safety, it is recommended this system be tested for acceptance as an RMS approved barrier system. Stopping sight distance (SSD) is the distance required to enable a driver to perceive, react and break to a stop before reaching a hazard on the road ahead. SSD is frequently viewed as an overriding parameter which directly relates to road safety within the road design community. The literature review revealed that the SSD model was based on a number of 85th percentiles combined with a small hazard being on the roadway. This has created quite a conservative design parameter which is often difficult to achieve, especially in constrained environments. The model may also stretch the limits of human abilities. The significant reduction of SSD at the sites, ranging from achieving 33-100% of the required SSD value, did not directly result in significant increase in crash severity. There was no distinct relationship between the degree of SSD reduction and increase in crashes. A less conservative, more realistic model such as ‘SSD over barriers’ is more suited to the constrained road environment. This model sights to a vehicle brake light or top of car and requires the provision of a 2.5m lane for manoeuvring around the object. However, as most sites failed to meet this model, no link between meeting ‘SSD over barrier’ and the reduction in crash severity was observed. Consequential poor pavement drainage at one site was likely to have attributed to a significant increase in wet pavement crashes. This is likely related to the cast in-situ concrete barrier which had only small drainage slots. The slots were not likely to relieve adequate pavement flows and may have led to aquaplaning. A site on the Princes Highway at East Lynne has been selected to apply the results and conclusions drawn from this study

On the importance of driver models for the development and assessment of active safety: A new collision warning system to make overtaking cyclists safer

The total number of road crashes in Europe is decreasing, but the number of crashes involving cyclists is not decreasing at the same rate. When cars and bicycles share the same lane, cars typically need to overtake them, creating dangerous conflicts—especially on rural roads, where cars travel much faster than cyclists. In order to protect cyclists, advanced driver assistance systems (ADAS) are being developed and introduced to the market. One of them is a forward collision warning (FCW) system that helps prevent rear-end crashes by identifying and alerting drivers of threats ahead. The objective of this study is to assess the relative safety benefit of a behaviour-based (BB) FCW system that protects cyclists in a car–to–cyclist overtaking scenario. Virtual safety assessments were performed on crashes derived from naturalistic driving data. A series of driver response models was used to simulate different driver reactions to the warning. Crash frequency in conjunction with an injury risk model was used to estimate the risk of cyclist injury and fatality. The virtual safety assessment estimated that, compared to no FCW, the BB FCW could reduce cyclists’ fatalities by 53–96% and serious injuries by 43–94%, depending on the driver response model. The shorter the driver’s reaction time and the larger the driver’s deceleration, the greater the benefits of the FCW. The BB FCW also proved to be more effective than a reference FCW based on the Euro NCAP standard test protocol. The findings of this study demonstrate the BB FCW’s great potential to avoid crashes and reduce injuries in car–to–cyclist overtaking scenarios, even when the driver response model did not exceed a comfortable rate of deceleration. The results suggest that a driver behaviour model integrated into ADAS collision threat algorithms can provide substantial safety benefits

Does a video speed task predict risky speeding behaviour in young and inexperienced drivers?

Vehicle crashes account for the highest number of fatalities for persons aged between 17 and 25 years of age in New Zealand. Despite a myriad of factors precipitating vehicle crashes, excess or inappropriate vehicle speed has been identified as the greatest predictor of crash likelihood and severity. Excess or inappropriate speed reduces a driver’s control over the vehicle, while exaggerating both collision force and the distances required in stopping or safely manoeuvring. One of the major differences identified between young and inexperienced and older more experienced drivers is the ability to adapt driving behaviour to road conditions. Young drivers are more prone to speeding through both a lack of awareness of risks and a desire to seek out novel and stimulating experiences. Recent developments in cognitive models of risk taking propose that older more experienced drivers may adapt their speed by “feeling out” the road conditions, where as young drivers may depend more upon posted limits to determine their speed. A video speed task was developed to measure speed preferences on a selection of road conditions (or ‘environments’) commonly confronting New Zealand motorists. Analyses of speed preferences revealed that young and inexperienced drivers preferred speeds close to the road-limit irrespective of conditions, whereas older and more experienced drivers preferred speeds clearly below the road limit, and demonstrated greater variation in speed preferences on different road environments. This suggests that young and inexperienced drivers both prefer faster speeds and may use the road limit as a target in determining an appropriate speed. Older and more experienced drivers prefer slower speeds, and adapt driving to changing road conditions. Faster preferred speeds were found to be related to a riskier attitudes towards driving in general, and more lenient attitudes toward speeding in particular. In addition, faster preferred speeds were found to be related to a heightened enjoyment of risk taking, as well as the number of speeding convictions issued in the previous 12 months. The used video speed task provided a convenient measure of speeding behaviour in natural driving scenarios, and appeared to be sensitive to differences in the way drivers adjust their behaviour across changing driving conditions. The video speed task might be useful in determining differences in speed choice between day and night time driving scenarios, as well as expanding the road conditions to including wet or foggy driving situations. This may be particularly useful in determining the pre- and post-effectiveness of driver training programs

Contributions to the 10th International Cycling Safety Conference 2022 (ICSC2022)

This publication contains all contributions (extended abstracts) to the 10th International Cycling Safety Conference, which was held in Dresden, Germany, Nov. 08-10, 2022