Driving Simulation Study Showed Trajectory Pointers in Automated Driving Systems Improved Driver Interventions, Reducing Collisions by 56-90 Percent.
A Total of 48 Participants Used Driving Simulator to Evaluate the Effect of an Enhanced Human-Machine Interface with Continuous Trajectory Feedback Pointers in Collision Scenarios.
Tokyo, Japan
Improvement of driver active interventions during automated driving by displaying trajectory pointers—A driving simulator study
Summary Information
In Automated Driving Systems (ADS), the transfer of vehicle control from automated to manual operation is quite critical, in the event that the ADS may fail to properly detect an obstacle on the road. Such a critical transfer of vehicle control demands an effective Human–Machine Interface (HMI). This study used a driving simulator with 48 participants to develop an HMI that constantly indicates the future position of the vehicle and enables the driver to be alert and ready in the event of any necessary takeover of vehicle control. This study evaluated the proposed HMI by comparing it with an HMI that notifies the driver only when the vehicle trajectory changes.
METHODOLOGY
In this study, a total of 48 test subjects were divided into two groups of 24: One group used the HMI that constantly indicated the future position of the vehicle (Continuous Trajectory Pointer (CTP)-based HMI), and the other group used the HMI that provided information only when the vehicle trajectory changed (Notification of Trajectory Changes (NTC)-based HMI). In the driving simulator experiments, the CTPs indicated the lateral position of the driver’s vehicle one, two, and three seconds into the future. In the evaluation period, a scenario in which the ADS failed to detect an obstacle on the vehicle trajectory was considered, potentially resulting in a collision if the driver fails to actively take over control and manually avoid the collision with the obstacle. The driving simulator experiments using the ADS lasted approximately 20 minutes and simulated a 25-km (about 23.4 miles) stretch of a two-lane, two-way urban expressway.
FINDINGS
- Results indicated that the use of the CPT-based HMI or NTC-based HMI can reduce the collisions by 56-90 percents.
- This study also estimated that the average Time to Collision (The time left before two moving objects collide) when the NTC-based HMI participant group grasped the steering wheel was 2.20 seconds, whereas that of the CTP-based HMI group was 4.02 seconds, indicating 82.7 percent faster reaction time by the CPT-based HMI participants to get their hands on the steering wheel and take over vehicle control when necessary.
