The Effect of Secondary Cognitive Task Difficulty on Headway Maintenance and Perceived Workload While Using Lane Keeping Systems

Vehicle automation is developing at a rapid rate worldwide. However, even lower levels of automation, such as SAE Level-1, are expected to reduce drivers’ workload by controlling either speed or lane position. At the same time, however, drivers’ engagement in secondary tasks may make up for this difference in workload displaced by automation. Previous research has investigated the effects of adaptive cruise control on driving performance and workload, but little attention has been devoted to lane keeping systems (LKS). In addition, the influence of secondary cognitive tasks on Level-1 driving performance is also not well understood. The goal of this study was to examine the effects of secondary cognitive tasks on driving performance and perceived workload while using LKS. Nine participants drove a simulated vehicle in manual and LKS modes, while maintaining a specific headway and performing a secondary cognitive (n-back) task with varying levels of difficulty. Results showed that standard deviation of headway and NASA-TLX workload scores were significantly higher during the most difficulty secondary task. Also, LKS was not found to improve driving performance nor reduce perceived workload. This paper highlights potential performance costs and benefits associated with LKS technology and proposes directions for future research.