Nuisance vs False Collision Warnings During Driving; The Difference in Effect of False and Nuisance Alarms on the Driver when Driving with a Forward Collision Warning System

Abstract: As a diverse field of advanced driver assistance systems (ADAS) aredeveloped and incorporated into the driving environment the need foranalysis of their effects on the driver becomes increasingly important. AsADAS gain more influence on the driving task they change how we drivewith a great potential for increasing the safety of the driver and thosein his/her vicinity. There is however also a potential problem with theincreasing amount of aids, if tuned incorrectly they may decrease safetyinstead; it is therefore of vital importance that the effects of aids and howthey relate to potentially hazardous situations is well understood.This thesis strives to provide a contribution to the research field ofADAS in order to increase safety in the driving environment, specificallyin the area of trust in frontal collision warning (FCW) systems under dif-ferent circumstances. Tests were carried out in a solid base driving simula-tor where reaction times were measured, followed by subjective measure-ment of workload by means of NASA-TLX questionnaire and subjectiveratings of trust by means of a novel questionnaire based on the APT-framework[12].The test was between groups by design where one group drove a sce-nario using a FCW system prone to giving nuisance alarms and the othergroup a similar scenario with a FCW system prone to false positive alarms.The FCW used was similar to that used in Volvo's cars. Both scenariospresented the test subject with 6 alarm situations, of which two where dif-ferent between the scenarios. Each scenario proceeded for 12-14 minutesdepending on speed and reactions to events.No significant differences was found between the two groups in any areaof data extracted. It is concluded that there is no difference in impact ofnuisance and false positive alarms in either of the areas of performance,workload or trust as they were constructed here. There is evidence ofthe participants rating the type of alarms differently between the groups,supporting this conclusion. Reaction times lie well within what can beconsidered normal during real driving, indicating that the data found canbe useful in further studies in the area of ADAS.The results of this study needs to be further tested but it carries someimplications for the algorithms used in FCW systems in what types ofalarms should be triggered. A proposed continuation of this study is inthe relation between true positive alarms and nuisance alarms to furtherdefine the role of nuisance alarms, as well as a longitudinal study showingthe long term effects of nuisance alarms.