| 1. |
- Bianchi Piccinini, Giulio, 1982, et al.
(författare)
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How Do Drivers Respond to Silent Automation Failures? Driving Simulator Study and Comparison of Computational Driver Braking Models
- 2020
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Ingår i: Human Factors. - Chalmers University of Technology, Gothenburg, Sweden.; Volvo Group Trucks Technology, Gothenburg, Sweden.; Virginia Tech Transportation Institute, Blacksburg, USA.; University of Leeds, UK.; VTI, Gothenburg, Sweden. : SAGE Publications. - 1547-8181 .- 0018-7208. ; 62:7, s. 1212-1229
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Tidskriftsartikel (refereegranskat)abstract
- Objective: This paper aims to describe and test novel computational driver models, predicting drivers’ brake reaction times (BRTs) to different levels of lead vehicle braking, during driving with cruise control (CC) and during silent failures of adaptive cruise control (ACC). Background: Validated computational models predicting BRTs to silent failures of automation are lacking but are important for assessing the safety benefits of automated driving. Method: Two alternative models of driver response to silent ACC failures are proposed: a looming prediction model, assuming that drivers embody a generative model of ACC, and a lower gain model, assuming that drivers’ arousal decreases due to monitoring of the automated system. Predictions of BRTs issued by the models were tested using a driving simulator study. Results: The driving simulator study confirmed the predictions of the models: (a) BRTs were significantly shorter with an increase in kinematic criticality, both during driving with CC and during driving with ACC; (b) BRTs were significantly delayed when driving with ACC compared with driving with CC. However, the predicted BRTs were longer than the ones observed, entailing a fitting of the models to the data from the study. Conclusion: Both the looming prediction model and the lower gain model predict well the BRTs for the ACC driving condition. However, the looming prediction model has the advantage of being able to predict average BRTs using the exact same parameters as the model fitted to the CC driving data. Application: Knowledge resulting from this research can be helpful for assessing the safety benefits of automated driving.
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| 2. |
- Engström, Johan A Skifs, 1973, et al.
(författare)
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Adaptive behavior in the simulator: Implications for active safety system evaluation
- 2011
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Ingår i: Handbook of Driving Simulation for Engineering, Medicine, and Psychology. - 9781420061017 ; , s. 41-1-41-16-
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- The Problem. Driving is, most of the time, a self-paced task where drivers proactively control the driving situation, based on their expectations of how things will develop in the near future. Crashes are typically associated with unexpected events where this type of proactive adaptation failed in one way or another. These types of scenarios are the main targets for active safety systems. In evaluation studies, drivers’ responses to expected events may be qualitatively different from responses to similar, but unexpected, events. Hence, creating artificial active safety evaluation scenarios that truly represent the targeted real-world scenarios is a difficult challenge. Role of Driving Simulators. Driving simulators offer great possibilities to test active safety systems with real drivers in specific target scenarios under tight experimental control. However, in simulator studies, experimental control generally has to be traded against realism. The objective of this chapter is to address some key problems related to driver expectancy and associated adaptive behavior in the context of simulator-based active safety system evaluation. Key Results of Driving Simulator Studies. The chapter briefly reviews common types of adaptive driver strategies found in the literature and proposes a general conceptual framework for describing adaptive driver behavior. Based on this framework, some key challenges in dealing with these types of issues in simulator studies are identified and potential solutions discussed. Scenarios and Dependent Variables. Key variables representing adaptive driver behavior include the selection of speed, headway, and lane position as well as the allocation of attention and effort. It will never be possible to create artificial simulator scenarios for active safety evaluation that perfectly match their real-world counterparts, but there are several means that could be used to reduce the discrepancy. Problems with expectancy and resulting adaptive behavior may at least be partly overcome by various means to “trick” drivers into critical situations, several of which are addressed in the chapter. Platform Specificity and Equipment Limitations. The issues discussed in this chapter should apply across all types of driving simulator platforms. However, some of the proposed methods for tricking drivers into critical situations may require specific simulator features, such as a motion base.
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| 3. |
- Engström, Johan A Skifs, 1973, et al.
(författare)
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Effects of working memory load and repeated scenario exposure on emergency braking performance
- 2010
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Ingår i: Human Factors. - : SAGE Publications. - 1547-8181 .- 0018-7208. ; 52:5, s. 551-559
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The objective of the present study was to examine the effect of working memory load on drivers' responses to a suddenly braking lead vehicle and whether this effect (if any) is moderated by repeated scenario exposure. Background: Several experimental studies have found delayed braking responses to lead vehicle braking events during concurrent performance of nonvisual, working memory-loading tasks, such as hands-free phone conversation. However, the common use of repeated, and hence somewhat expected, braking events may undermine the generalizability of these results to naturalistic, unexpected, emergency braking scenarios. Method: A critical lead vehicle braking scenario was implemented in a fixed-based simulator. The effects of working memory load and repeated scenario exposure on braking performance were examined. Results: Brake response time was decomposed into accelerator pedal release time and accelerator-to-brake pedal movement time. Accelerator pedal release times were strongly reduced with repeated scenario exposure and were delayed by working memory load with a small but significant amount (178 ms). The two factors did not interact. There were no effects on accelerator-to-brake pedal movement time. Conclusion:The results suggest that effects of working memory load on response performance obtained from repeated critical lead vehicle braking scenarios may be validly generalized to real world unexpected events. Application: The results have important implications for the interpretation of braking performance in experimental settings, in particular in the context of safety-related evaluation of in-vehicle information and communication technologies. © 2010, Human Factors and Ergonomics Society.
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| 4. |
- Ljung Aust, Mikael, 1973, et al.
(författare)
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A conceptual framework for requirement specification and evaluation of active safety functions
- 2011
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Ingår i: Theoretical Issues in Ergonomics Science. - : Informa UK Limited. - 1464-536X .- 1463-922X. ; 12:1, s. 44-65
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Tidskriftsartikel (refereegranskat)abstract
- Active safety functions intended to prevent vehicle crashes are becoming increasingly prominent in traffic safety. Successful evaluation of their effects needs to be based on a conceptual framework, i.e. agreed-upon concepts and principles for defining evaluation scenarios, performance metrics and pass/fail criteria. The aim of this paper is to suggest some initial ideas toward such a conceptual framework for active safety function evaluation, based on a central concept termed 'situational control'. Situational control represents the degree of control jointly exerted by a driver and a vehicle over the development of specific traffic situations. The proposed framework is intended to be applicable to the whole evaluation process, from 'translation' of accident data into evaluation scenarios and definition of evaluation hypotheses, to selection of performance metrics and criteria. It is also meant to be generic, i.e. applicable to driving simulator and test track experiments as well as field operational tests.
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| 5. |
- Ljung Aust, Mikael, 1973, et al.
(författare)
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Effects of forward collision warning and repeated event exposure on emergency braking
- 2013
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Ingår i: Transportation Research Part F: Traffic Psychology and Behaviour. - : Elsevier BV. - 1369-8478. ; 18, s. 34-46
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Tidskriftsartikel (refereegranskat)abstract
- Many experimental studies use repeated lead vehicle braking events to study the effects of forward collision warning (FCW) systems. It can, however, be argued that the use of repeated events induce expectancies and anticipatory behaviour that may undermine validity in terms of generalisability to real-world, naturalistic, emergency braking events. The main objective of the present study was to examine to what extent the effect of FCW on response performance is moderated by repeated exposure to a critical lead vehicle braking event. A further objective was to examine if these effects depended on event criticality, here defined as the available time headway when the lead vehicle starts to brake. A critical lead vehicle braking event was implemented in a moving-base simulator. The effects of FCW, repeated event exposure and initial time headway on driver response times and safety margins were examined. The results showed that the effect of FCW depended strongly on both repeated exposure and initial time headway. In particular, no effects of FCW were found for the first exposure, while strong effects occurred when the scenario was repeated. This was interpreted in terms of a switch from closed-loop responses triggered reactively by the situation, towards an open-loop strategy where subjects with FCW responded proactively directly to the warning. It was also found that initial time headway strongly determined response times in closed-loop conditions but not in open-loop conditions. These results raise a number of methodological issues pertaining to the design of experimental studies with the aim of evaluating the effects of active safety systems. In particular, the implementation of scenario exposure and criticality must be carefully considered.
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| 6. |
- Ljung Aust, Mikael, 1973, et al.
(författare)
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Manual for DREAM version 3.2
- 2012
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Driving Reliability and Error Analysis Method (DREAM) is based on the Cognitive Reliability and Error Analysis Method (CREAM; Hollnagel, 1998). CREAM was developed to analyse accidents within process control domains such as nuclear power plants and train operation, and DREAM is an adaptation of CREAM to suit the road traffic domain. The purpose of DREAM is to make it possible to systematically classify and store accident and incident causation information. This means that DREAM, like all other methods for accident/incident analysis, is not a provider but an organiser of explanations. For any of the contributing factor categories available in DREAM to be used, it must be supported by relevant empirical information. DREAM in itself cannot tell us why accidents happen (if it could, we would need neither on-scene investigations nor interviews).DREAM includes three main components: an accident model, a classification scheme and a detailed procedure description which step by step goes through what needs to be done in order to perform a DREAM analysis on an investigated accident/incident. Below, the accident model will be given more detailed descriptions. After this follows a description of the classification scheme, and then comes the analysis process, including example cases and recommendations for how to do the categorisation in certain typical scenarios.
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| 7. |
- Nilsson, Emma, 1982, et al.
(författare)
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Effects of cognitive load on response time in an unexpected lead vehicle braking scenario and the detection response task (DRT)
- 2018
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Ingår i: Transportation Research Part F: Traffic Psychology and Behaviour. - : Elsevier BV. - 1369-8478. ; 59, s. 463-474
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Tidskriftsartikel (refereegranskat)abstract
- The effects of cognitive distraction on traffic safety and driver performance are unclear and under debate. Based on increased response times to stimuli or events in controlled driving experiments, concerns, primarily about cell phone usage during driving, have been raised. But while cognitive load repeatedly have been shown to increase response times in artificial tasks such as the Detection Response Task (DRT), the generalizability of the results to response times in critical traffic situations is questionable. Method: Two experiments were conducted. In Experiment 1, response times in the DRT were measured during simulated driving with and without execution of a cognitively loading secondary task. In Experiment 2, brake response times in an unexpected lead vehicle braking scenario were measured with and without the same cognitively loading task. Results: In Experiment 1, DRT response times increased with increased level of cognitive load. In Experiment 2, brake response times were unaffected by cognitive load. Conclusion: The response time results from the artificial DRT did not generalize to the critical lead vehicle braking scenario. This finding can possibly be explained by the cognitive control hypothesis, which suggests that cognitive load selectively impairs driving subtasks that rely on cognitive control (i.e. novel or inconsistent tasks) but leaves automatic performance unaffected (Engström, Markkula, Victor, & Merat, 2017). While the DRT responses, because of the task novelty, can be assumed to require cognitive control, responses to visually expanding objects, such as a braking lead vehicle with short time headway, are triggered automatically. Common interpretations of the effect of cognitive load on traffic safety thus need to be re-examined. It seems inappropriate to generalize from effects of cognitive load on DRT, or other artificial laboratory tasks that rely on cognitive control, to unexpected real-world situations where responses are triggered primarily by looming cues.
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| 8. |
- Bianchi Piccinini, Giulio, 1982, et al.
(författare)
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Factors contributing to commercial vehicle rear-end conflicts in China: A study using on-board event data recorders
- 2017
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Ingår i: Journal of Safety Research. - : Elsevier BV. - 0022-4375. ; 62, s. 143-153
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: In the last 30 years, China has undergone a dramatic increase in vehicle ownership and a resulting escalation in the number of road crashes. Although crash figures are decreasing today, they remain high; it is therefore important to investigate crash causation mechanisms to further improve road safety in China. Method: To shed more light on the topic, naturalistic driving data was collected in Shanghai as part of the evaluation of a behavior-based safety service. The data collection included instrumenting 47 vehicles belonging to a commercial fleet with data acquisition systems. From the overall sample, 91 rear-end crash or near-crash (CNC) events, triggered by 24 drivers, were used in the analysis. The CNC were annotated by three researchers, through an expert assessment methodology based on videos and kinematic variables. Results: The results show that the main factor behind the rear-end CNC was the adoption of very small safety margins. In contrast to results from previous studies in the US, the following vehicles' drivers typically had their eyes on the road and reacted quickly in response to the evolving conflict in most events. When delayed reactions occurred, they were mainly due to driving-related visual scanning mismatches (e.g., mirror checks) rather than visual distraction. Finally, the study identified four main conflict scenarios that represent the typical development of rear-end conflicts in this data. Conclusions: The findings of this study have several practical applications, such as informing the specifications of in-vehicle safety measures and automated driving and providing input into the design of coaching/training procedures to improve the driving habits of drivers.
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| 9. |
- Bärgman, Jonas, 1972, et al.
(författare)
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ANNEXT - Slutrapport
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Huvudmålet med ANNEXT har varit att utvärdera och illustrera styrkan i att använda redan insamlade externa naturalistiska kördata från DriveCams datainsamling (www.drivecam.com), för att öka förståelsen kring vad som orsakar trafikolyckor. Fram till nyligen har det inte funnits data som medger detaljerade studier av vad som sker i de viktiga sekunderna precis innan en olycka (eller nästan-olycka) i verklig trafik. Det vill säga, det har inte varit möjligt att studera t.ex. förares aktiviteter (t.ex. distraktioner såsom mobilanvändande) eller hur interaktionen mellan fordonen och dess förare faktiskt gått till under sekunderna före krock. Vi har använt oss av data from händelseinitierade inspelningsenheter i kommersiella fordon, där data inte samlats in som en del i något forskningsprojekt, utan som en del i en affärsverksamhet där DriveCam sålt en tjänst till företag som har flottor med fordon. Det vill säga, dessa händelseinspelare installeras inte i fordon för att specifikt forska på orsaker till olyckor, utan som en del i en tjänst för att förbättra trafiksäkerheten för just dessa företag. Ett tydligt mål är att få ner stilleståndskostnader för företagens fordon vid olyckor, men det har också effekten att antalet olyckor (och därmed skadade och dödade) minskar på vägarna där de körs. Fordonen körs som en del i den vanliga verksamheten hos företagen. När en olycka eller nästan-olycka identifieras med hjälp av kinematiska triggers (t.ex. tröskelvärden på acceleration), sparas data 8 sekunder föra och 4 sekunder efter triggern i inspelningsenheten. Data innefattar bl.a. GPS, video på föraren och framåt samt accelerometerdata. Denna skickas sedan tillbaks till DriveCam där en genomgång av alla händelser görs och varje event klassas för trafiksäkerhetsrelevans. I ANNEXT har vi fått tillgång till 100 påkörandehändelse (70 olyckor och 30 nästan-olyckor) samt 93 korsningshändelser (63 olyckor och 30 nästan-olyckor). Alla händelser har kodats av DriveCam-personal och vi på SAFER har sedan analyserat data. Följande beskriver processen genom projektet: Första steget var att ta fram en preliminär analysplan, baserad på projektansökan och ytterligare identifierade behov. Steg två var att kontakta DriveCam och få till ett kontrakt inom vilkets ramar projektet kunde genomföras. Scenarios identifierades och kriterier för hur händelser skulle väljas ut utvecklades och itererades mot DriveCam. Detaljerna är beskrivna i en publikation (Engström, Werneke, et al., 2013) från projektet (se separat avsnitt). Analysplanen har förfinats allteftersom i projektet. Som en del i analysplanen utvecklades en annoteringsbeskrivning, eller kodbok. Denna beskriver de variabler som vi identifierat som nödvändiga för analysen och som kräver manuell annotering av DriveCam-video. I ANNEXT utförde en dedikerad annoterare på DriveCam all primär videoannotering. För att förfina kodboken och verifiera annotering åkte SAFER-deltagare till DriveCam vid två tillfällen. När den huvudsakliga annotering var avslutad genomförde SAFER-partners 1) utveckling av metoder för extraktion av optiska parameterar baserat på annoterad video (Bärgman et al., 2013), och processade dessa data för att kvalitetssäkra inför analys, 2) iterativ vidareutveckling av kodningsschemat som kan kallas Kodbok för bidragandefaktorer (se resultat) och applicerade denna på tillgänglig data. Under våren och sommaren 2013 presenterades två vetenskapliga artiklar på konferenser. Ytterligare publikationer är under utveckling (se separat avsnitt)
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| 10. |
- Bärgman, Jonas, 1972, et al.
(författare)
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Using manual measurements on event recorder video and image processing algorithms to extract optical parameters.
- 2013
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Ingår i: Proceedings of the Seventh International Driving Symposium on Human Factors in Driver Assessment, Training and Vehicle Design. ; , s. 177-183
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Konferensbidrag (refereegranskat)abstract
- Vehicle kinematics and optical parameters such as optical angle, optical expansion rate, and tau are thought to underlie drivers’ ability to avoid and handle critical traffic situations. Analyses of these parameters in naturalistic driving data with video, such as commercial event recordings of near-crashes and crashes, can provide insight into driver behavior in critical traffic situations. This paper describes a pair of methods, one for the range to a lead vehicle and one for its optical angle, that are derived from image processing mathematics and that provide driver behavior researchers with a relatively simple way to extract optical parameters from video-based naturalistic data when automatic image processing is not possible. The methods begin with manual measurements of the size of other road users on a video on a screen. To develop the methods, 20 participants manually measured the width of a lead vehicle on 14 images where the lead vehicle was placed at different distances from the camera. An on-market DriveCam Event Recorder was used to capture these images. A linear model that corrects distortion and modeling optics was developed to transform the on-screen measurements distance (range) to and optical angle of the vehicle. The width of the confidence interval for predicted range is less than 0.1m when the actual distance is less than 10m and the lead-vehicle width estimate is correct. The methods enable driver behavior researchers to easily and accurately estimate useful kinematic and optical parameters from videos (e.g., of crashes and near-crashes) in event-based naturalistic driving data.
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| 11. |
- Eiríksdóttir, Hrafnhildur Hekla, 1988, et al.
(författare)
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The perfect mismatch: Analysis of rear-end crash causation mechanisms based on naturalistic crash data
- 2017
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Ingår i: 6th International Symposium on Naturalistic Driving Research. June 8-9. The Hague, The Netherlands.
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Konferensbidrag (refereegranskat)abstract
- The present analysis aimed to replicate the analysis of Victor et al. (2015), who investigated how off-road glances cause rear-end crashes and near-crashes. The key finding in Victor et al. (2015) was that many rear-end crashes occur due to a “perfect mismatch” between the timing of the last glance before the crash/near crash and the change in kinematics resulting from the lead vehicle braking. The present analysis, based on a set of event-triggered naturalistic crashes and near crashes obtained from commercial on-board safety monitoring devices, largely corroborated the previous findings and, additionally, developed a new metric that offered some further insight into the perfect mismatch mechanism.
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| 12. |
- Engström, Johan A Skifs, 1973
(författare)
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A model of attention selection in driving
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Inattention is one of the most common factors contributing to road crashes. However, the basic mechanisms behind inattention and how it leads to crashes are still relatively poorly understood. The objective of the present thesis was to develop a testable model of attention selection in driving which could serve as the basis for a scientifically grounded taxonomy of drivers’ attention failures.A key starting point for the model development was that inattention needs to be understood within a broader framework of adaptive driver behaviour. A proposal for such a framework was outlined as the basis for the subsequent model development. At the core of the proposed model is an attention selection mechanism based on the biased competition hypothesis, which states that attention selection occurs through local competitive interactions which are biased top-down and/or bottom-up. The model is rooted within the embodied cognitive science tradition and adopts an activation dynamics-, rather than an information processing, metaphor. Still, the main concepts are largely compatible with traditional information processing models of attention, such as Multiple Resource Theory.The model was validated against existing empirical work on driver inattention, in particular the two studies reported in the appended papers, which investigated the effects of visual and cognitive secondary tasks on driving performance, behaviour and state. It was demonstrated how the model offers novel explanations for several observed phenomena not which do not seem to be accounted for by existing models. Moreover, a number of novel predictions were generated which could be tested in future empirical studies. It was also demonstrated how the model can be used as the basis for a taxonomy of attention-related failures and factors in driving.
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| 13. |
- Engström, Johan A Skifs, 1973, et al.
(författare)
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Analysis of the role of inattention in road crashes based on naturalistic on-board safety monitoring data
- 2013
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Ingår i: PROCEEDINGS of the 3rd International Conference on Driver Distraction and Inattention.
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Konferensbidrag (refereegranskat)abstract
- The general objective of the present analysis was to investigate the role of driver inattention in rear-end crashes and crossing path intersection crashes. To this end, a set of 133 naturalistic crashes (70 rear-end and 63 intersection crashes), obtained by means of the DriveCam on-board safety monitoring (OBSM) system, were analyzed based on a novel methodology for assigning and aggregating crash-contributing factors. The analysis focused on rear-end crashes where the OBSM-instrumented vehicle was striking a lead vehicle and crossing-path intersection crashes where the driver of the instrumented vehicle intended to proceed straight through the intersection. It was found that driver inattention, in particular driver distraction involving a diversion of gaze from the forward roadway, was the dominating factor contributing to the rear-end crashes.Although driver inattention also contributed to the intersection crashes, the patterns of contributing factors for this crash type were quite different compared to the rear-end crashes. In particular, in the intersection crashes, visual occlusion and insufficient selection of safety margins were identified as key contributing factors. Cognitively distracting activities that did not involve a diversion of gaze from the forward roadway, such as cell phone conversation, did not contribute frequently to avoidance failures for any of the crash types. The present results show that the role of driver inattention as acrash-contributing factor depends strongly on the type of crash. They also support previous findings from naturalistic driving studies that visual diversion from theforward roadway is the key mechanism by which inattention leads to rear-end crashes.
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| 14. |
- Engström, Johan A Skifs, 1973, et al.
(författare)
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Attention selection and multitasking in everyday driving: A conceptual model
- 2013
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Ingår i: Driver Distraction and Inattention: Advances in Research and Countermeasures. - 9781409425854 ; , s. 27-54
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter outlines a conceptual model of attention selection and multitasking in everyday driving. While existing theoretical and empirical work on attention in driving has mainly focused on dual-task interference in experimental settings, the present model aims to account for attention selection in natural driving situations. The model starts from the view of attention as a form of adaptive behaviour and emphasises the key role of expectancy, the dynamic interplay between top-down and bottom-up selection, the often habitual nature of attention selection in real driving and how attention selection is driven by perceived and expected value. However, the model also offers a novel characterisation of dual-task interference mechanisms and more precise definitions of key concepts such as driver inattention and driver distraction. Based on the model, a general conceptualisation of the relation between attention selection and crash causation is proposed and implications for the design of driver support systems and automotive human-machine interfaces are discussed.
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| 15. |
- Engström, Johan A Skifs, 1973
(författare)
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EFFECTS OF VISUAL AND COGNITIVE DISTRACTION ON LANE CHANGE TEST PERFORMANCE
- 2008
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Ingår i: 2007.
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Konferensbidrag (refereegranskat)abstract
- Driver errors related to visual and cognitive distraction were studied in the context of the Lane Change Test (LCT). New performance metrics were developed in order to capture the specific effects of visual and cognitive distraction. In line with previous research, it was found that the two types of distraction impaired driving in different ways. Visual, but not cognitive, distraction led to reduced path control. By contrast, only cognitive distraction affected detection and recognition/response selection. Theoretical and practical implications of these results are discussed.
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| 16. |
- Engström, Johan A Skifs, 1973, et al.
(författare)
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Evaluation Framework for Commercial Vehicle Safety Systems and Services (EFrame). Final Report
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The main project aim was to develop a structured framework for traffic safety evaluation in an industrial (commercial vehicle manufacturer) context. The resulting framework facilitates more efficient development of crash/injury countermeasures by (1) identifying and focusing on the most important safety problems, (2) estimating the potential and actual safety benefits of safety systems and services and (3) identifying the data sources needed to perform these analyses.The project started with identification of the general types of safety evaluation analyses needed from an industrial development perspective (the Evaluation Use Cases, EUCs). The EUCs helped to keep the project focused, in spite of its broad general scope, and constituted the basis for all remaining work in the project (WP1). Next, an initial sketch of the framework, in terms of the data sources and analysis needed to address the EUCs were developed (WP1). This was followed by a comprehensive state-of-the-art review of existing data sources and road safety analysis methodologies that could potentially be used as components in the framework (WP2). Based on this, existing methods were adapted, or novel methods developed, to address the Evaluation Use Cases (WP3). Finally, the methods adapted/developed in WP3 were applied to a set of concrete evaluation test cases in order to demonstrate the framework and identify needs for further improvement (WP4). Based on this, the final framework was defined (WP4). Thus, the project objectives have generally been met, although further development and testing is needed on other concrete test cases beyond than those addressed in WP4.The framework has the potential to reduce the number of killed and injured in traffic by focusing industrial development and academic research on the most effective safety systems and services and increases AB Volvo’s international competitiveness by further strengthening its safety system/services offering. The project has also, thanks to its broad scope, fostered increased collaboration between different sub-fields of traffic safety analysis (e.g., passive safety, active safety and road user behavior analysis) and thus contributed to the development of a critical mass of competence at SAFER/Chalmers/Volvo in this area.
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| 17. |
- Engström, Johan A Skifs, 1973, et al.
(författare)
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Final framework specification for Evaluation Framework for Commercial Vehicle Safety Systems and Services (EFrame)
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The objective of the EFrame FFI project was to develop a structured framework for traffic safety evaluation in an industrial (commercial vehicle manufacturer) context. The resulting framework facilitates more efficient development of crash/injury countermeasures by identifying and focusing on the most important safety (crash) problems, providing a toolset for analyzing crashes and estimating the potential and actual effectiveness of safety systems and services and, finally, identifying the data sources needed to perform these analyses. A general overview of the project and its results can be found in the Final Report (Engström and Wege, 2016)The project started with identification of the general types of safety evaluation needed from an industrial development perspective (the Evaluation Use Cases, EUCs). The EUCs helped to keep the project focused, in spite of its broad general scope, and constituted the basis for all remaining work in the project.
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| 18. |
- Engström, Johan A Skifs, 1973, et al.
(författare)
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Great expectations: A predictive processing account of automobile driving
- 2018
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Ingår i: Theoretical Issues in Ergonomics Science. - 1464-536X .- 1463-922X. ; 19:2, s. 156-194
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Tidskriftsartikel (refereegranskat)abstract
- Predictive processing has been proposed as a unifying framework for understanding brain function, suggesting that cognition and behaviour can be fundamentally understood based on the single principle of prediction error minimisation. According to predictive processing, the brain is a statistical organ that continuously attempts get a grip on states in the world by predicting how these states cause sensory input and minimising the deviations between the predicted and actual input. While these ideas have had a strong influence in neuroscience and cognitive science, they have so far not been adopted in applied human factors research. The present paper represents a first attempt to do so, exploring how predictive processing concepts can be used to understand automobile driving. It is shown how a framework based on predictive processing may provide a novel perspective on a range of driving phenomena and offer a unifying framework for traditionally disparate human factors models.
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| 19. |
- Engström, Johan A Skifs, 1973, et al.
(författare)
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Real-Time Distraction Countermeasures
- 2008
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Ingår i: Driver Distraction: Theory, Effects, and Mitigation. - 9781420007497 ; , s. 465-484
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In general terms, distraction can be defi ned as misallocated attention.1 In the context of driving, distraction could be induced by a range of activities such as looking after children, looking for road signs, applying makeup, and using in-vehicle information systems. Distraction may also be purely “internally” triggered, for example when daydreaming. A large body of empirical research links driver distraction to degraded driving performance, for example, reduced lateral control, reduced event and object detection performance, and impaired decision making (see, e.g., Young et al.2 for a review). Distraction has also repeatedly been identifi ed as a major contributing factor in crashes, 3-5 although direct causal links between distraction-induced performance degradation and actual crash risk have been diffi cult to establish empirically. This is due mainly to the methodological diffi culties associated with collecting suffi ciently detailed precrash data. However, recent results from naturalistic fi eld studies, such as the 100-car study, 6, 7 have contributed to bridging this gap (see Chapters 16 and 17), by demonstrating signifi cant increases in (relative) risk resulting from driver engagement in a variety of distracting activities.
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| 20. |
- Engström, Johan A Skifs, 1973
(författare)
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Understanding attention selection in driving: From limited capacity to adaptive behaviour
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Accident analysis studies have consistently identified attention-related failures as key factors behind road crashes. However, less is known about how such failures lead to accidents. Traditionally, one reason for this knowledge gap has been a lack of sufficiently detailed data from the pre-crash phase, although this situation is currently changing with the advent of naturalistic driving studies. However, a remaining issue is the lack of an adequate conceptual model of attention selection applicable in natural driving situations. Existing attention models applied in the driving domain are generally based on the notion of attention as a resource with limited capacity, subject to overload in demanding conditions. Such models have mainly focused on dual task interference in experimental situations and but have put less emphasis on aspects central to attention selection in everyday driving such as expectancy and anticipatory attention allocation. The general objective of the present thesis was to obtain a better understanding of the relation between attention, performance and crash risk in real driving situations. To this end, a general conceptual framework for understanding attention selection in natural driving was developed, based on the view of attention selection as a form of adaptive behaviour rather than a consequence of limited information processing capacity. This also involved the development of a specific model of attention selection mechanisms and a series of empirical studies to support the model development. The main objective of these studies was to better understand the effects of working memory (or cognitive-) load on driving performance and the key mechanisms behind expectancy and proactive attention scheduling in driving. A key finding was that working memory load appears to selectively affect aspects of driving performance that can be characterised as controlled, while leaving reflexive and habitual, automatic, behaviours largely unaffected, an idea that resolves several inconsistent findings in the existing literature. Based on the proposed model, precise definitions of attention, expectancy, driver inattention and driver distraction were proposed. The thesis also suggests a general conceptualisation of the relation between attention selection and crashes. Finally, practical applications of the present findings in the areas of accident and incident analysis, countermeasure development and evaluation methods are discussed.
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| 21. |
- Husberg, Tobias, 1975, et al.
(författare)
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Piston temperature measurement by use of thermographic phosphors and thermocouples in a heavy-duty diesel engine run under partly premixed conditions
- 2005
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
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Tidskriftsartikel (refereegranskat)abstract
- Piston temperature experiments were conducted in a single-cylinder heavy-duty Diesel research engine, based on the Volvo Powertrain D12C engine both by use of optical temperature sensitive phosphor and of thermocouples mounted on the piston surface. In the former case, a thin coating of a suitable thermographic phosphor was applied to the areas on the piston surface to be investigated. The optical measurements of piston temperatures made involved use of an optical window and of an endoscope. The possibility of using optical fibres into guide light in and out of the engine was also investigated. Results of the optical and of the thermocouple measurements were compared and were also related to more global data with the aim of exploring the use of thermographic phosphors for piston- temperature measurements in Diesel engines. Thermographic phosphors thermometry was found to represent an alternative to the thermocouple method since it easily can be applied to various piston geometries. The method was seen to have a clear potential for production-type engine applications, particularly with use of fibre optics. Copyright © 2005 SAE International.
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| 22. |
- Markkula, Gustav M, 1978, et al.
(författare)
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A farewell to brake reaction times? Kinematics-dependent brake response in naturalistic rear-end emergencies
- 2016
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Ingår i: Accident Analysis and Prevention. - : Elsevier BV. - 0001-4575. ; 95, s. 209-226
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Tidskriftsartikel (refereegranskat)abstract
- Driver braking behavior was analyzed using time-series recordings from naturalistic rear-end conflicts (116 crashes and 241 near-crashes), including events with and without visual distraction among drivers of cars, heavy trucks, and buses. A simple piecewise linear model could be successfully fitted, per event, to the observed driver decelerations, allowing a detailed elucidation of when drivers initiated braking and how they controlled it. Most notably, it was found that, across vehicle types, driver braking behavior was strongly dependent on the urgency of the given rear-end scenario's kinematics, quantified in terms of visual looming of the lead vehicle on the driver's retina. In contrast with previous suggestions of brake reaction times (BRTs) of 1.5 s or more after onset of an unexpected hazard (e.g., brake light onset), it was found here that braking could be described as typically starting less than a second after the kinematic urgency reached certain threshold levels, with even faster reactions at higher urgencies. The rate at which drivers then increased their deceleration (towards a maximum) was also highly dependent on urgency. Probability distributions are provided that quantitatively capture these various patterns of kinematics-dependent behavioral response. Possible underlying mechanisms are suggested, including looming response thresholds and neural evidence accumulation. These accounts argue that a naturalistic braking response should not be thought of as a slow reaction to some single, researcher-defined "hazard onset", but instead as a relatively fast response to the visual looming cues that build up later on in the evolving traffic scenario.
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| 23. |
- Sagberg, Fridulv, et al.
(författare)
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A Review of Research on Driving Styles and Road Safety
- 2015
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Ingår i: Human Factors. - : SAGE Publications. - 1547-8181 .- 0018-7208. ; 57:No. 7, November 2015, s. 1248- 1275
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Forskningsöversikt (refereegranskat)abstract
- Objective: To outline a conceptual framework for understanding driving style and, based on this, review the state-of-the-art research on driving styles in relation to road safety.Background: Previous research has indicated a relationship between the driving styles adopted by drivers and their crash involvement. However, a comprehensive literature review of driving style research is lacking. Method: A systematic literature search was conducted, including empirical, theoretical and methodological research on driving styles related to road safety. Results: A conceptual framework was proposed where driving styles are viewed in terms of driving habits established as a result of individual dispositions as well as social norms and cultural values. Moreover, a general scheme for categorising and operationalizing driving styles was suggested. On this basis, existing literature on driving styles and indicators was reviewed. Links between driving styles and road safety were identified and individual and socio-cultural factors influencing driving style were reviewed. Conclusion: Existing studies have addressed a wide variety of driving styles, and there is an acute need for a unifying conceptual framework in order to synthesise these results and make useful generalisations. There is a considerable potential for increasing road safety by means of behaviour modification. Naturalistic driving observations represent particularly promising approaches to future research on driving styles. Application: Knowledge about driving styles can be applied in programmes for modifying driver behaviour and in the context of usage-based insurance. It may also be used as a means for driver identification and for the development of driver assistance systems.
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| 24. |
- Svärd, Malin, 1985, et al.
(författare)
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A quantitative driver model of pre-crash brake onset and control
- 2017
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Ingår i: Proceedings of the Human Factors and Ergonomics Society. - : SAGE Publications. - 1071-1813 .- 2169-5067. ; 61:1, s. 339 - 343
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Konferensbidrag (refereegranskat)abstract
- An existing modelling framework is leveraged to create a driver braking model for use in simulations of critical longitudinal scenarios with a slower or braking lead vehicle. The model applies intermittent brake adjustments to minimize accumulated looming prediction error. It is here applied to the simulation of a set of lead vehicle scenarios. The simulation results in terms of brake initiation timing and brake jerk are demonstrated to capture well the specific types of kinematics-dependencies that have been recently reported from naturalistic near-crashes and crashes.
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| 25. |
- Victor, Trent, 1968, et al.
(författare)
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Analysis of Naturalistic Driving Study Data: Safer Glances, Driver Inattention, and Crash Risk
- 2014
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This work was sponsored by the secondStrategic Highway Research Program (SHRP 2), which isadministered by the Transportation Research Board of the National Academies. This project wasmanaged by Ken Campbell, Chief Program Officer for SHRP 2 Safety, and Jim Hedlund,SHRP 2SafetyCoordinator.The research reported on herein was performed by the main contractor SAFER Vehicle and TrafficSafety Centre at Chalmers, Gothenburg, Sweden. SAFER is a joint research unit where 25 partnersfrom the Swedish automotive industry, academia and authoritiescooperate to make a center ofexcellence within the field of vehicle and traffic safety (seewww.chalmers.se/safer). The host andlegal entity SAFER is Chalmers University of Technology. Principle Investigator Trent Victor is AdjunctProfessor at Chalmers and worked on the project as borrowed personnel to Chalmers but his mainemployer is Volvo Cars. The other authors of this report are Co-PI Marco Dozza, Jonas Bärgman, andChristian-Nils Boda of Chalmers University of Technology(as a SAFER partner); Johan EngströmandGustav Markkulaof Volvo Group Trucks Technology(as a SAFER partner); John D. Lee of Universityof Wisconsin-Madison (as a consultant to SAFER); and Carol Flannagan of University of MichiganTransportation Research Institute (UMTRI) (as a consultant to SAFER). The authors acknowledge thecontributions to this research from Ines Heinig, Vera Lisovskaja, Olle Nerman, Holger Rootzén,Dmitrii Zholud, Helena Gellerman, Leyla Vujić, Martin Rensfeldt,Stefan Venbrant, Akhil Krishnan,Bharat Mohan Redrouthu, Daniel Nilssonof Chalmers; Mikael Ljung-Aust of Volvo Cars; Erwin Boer;Christer Ahlström and Omar Bagdadi of VTI.
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