Publication

The development in the car industry is going towards autonomous cars where the borderbetween a driver and a passenger is gradually diminished. In the future the driver will be more similar to a passenger since the driving will be outsourced to the car. There is a knowledge gap regardingthe front seat passenger thatneeds to be filled with information. The passengerdoes not like the driver keep track of the road or use the steering wheel for support while riding in turns. Therefor they are likely to be more exposed to the lateral acceleration and lateral movement in turns.The aim of this thesis was to investigate how lateral movement affect the front seat passenger. In order to do this three studies were conducted, including one pre-study to set the knowledge foundation and to find criticaluser groups and roads. The smaller tests that constituted the pre-studyincluded a lot of driving and collecting velocities, lateral acceleration and estimated lateral movement. Among other things the pre-study resulted in a definition of normal driving in turns anda route for user study one,including interesting turns to investigate. Lastly,it resulted in an evaluation of the parameters affecting lateral movement on the front seat passenger and fourparameterswere chosen for user study one, body height, BMI, velocity and type of turn.The result from the pre-study was used to design user study one, a user study including26 participants with varying heights and BMItraveling in the front seat in a real traffic environment.The subjects were video recorded and interviewed which resulted in both quantitative and subjective data to analyse. The conclusion from user studyone wasthat short people aremost exposed to lateral movement in turns and the type of turns that generate the most lateral movement was found to be roundabouts driven in 28 km/h. Oneunexpected insight was that many of the subjects supported themselves on the midpanel andon theside support which decreased their lateral movement. This wasmostly done by tall people which can partly explain why they were exposed to less lateral movement.User study two focused on acriticaluser groupand velocity, short people riding in 28 km/h,with 14 participants.The aim of this user study was to investigate how lateral movement of the front seat passenger is affected by road awareness, the ability to use support fromthemiddle andside panels and lastly to evaluate a pre-pretensioningbelt conceptwith the purposeto decrease lateral movement. This test was executed on a test route to ensure repeatabilityand efficiency. The subjects got assignments to do while riding in the turn to decrease their road awareness and take away the ability to support themselves on the side panels.During the test the subjects were also exposed to a tension belt during some of the turns to investigate their attitude towards it and whether it decreases lateral movement. The assignmentsdidnot increase lateral movement butmost subjects did not appreciate doing activities while turning. None of the pre-pretensioningbelts decreased lateral movement andthe subject’sattitudestowards themwere scattered.The study concluded in that lateral movement does sometimes result in non-optimal body positions but does not decrease theride comfort during normal drive. If the passenger is doing an activity while riding in aturn, lateral movement decreases comfort and execution efficiency, something that needs to be further investigated in future studies to ensure high ride comfort fordrivers of autonomous cars. There is a vast amount of ways to decrease lateral movement without decreasing velocity andonly one was tested in this study. If the tension belt is to befurther investigated,astronger force should be appliedandit is important that it is optionalto use, since the experience of it is highly individual.