RATIONALE & INTRODUCTION

As passengers take rides in fleet-managed automated driving system-dedicated vehicles (ADS-DVs), they may feel the need to interrupt the trip due to a perceived emergency. There is currently no industry consensus on the proper balance between ADS passenger agency and the potential for introducing unexpected outcomes in dynamic traffic environments. In order to build public trust in automated vehicles, passengers should be given an option to exercise some type of control (agency) to intervene during situations they perceive as emergencies. Passenger-initiated emergency trip interruption features — however they manifest in a given vehicle — can help establish this confidence in ADS technologies.

RATIONALE & INTRODUCTION

As passengers take rides in fleet-managed automated driving system-dedicated vehicles (ADS-DVs), they may feel the need to interrupt the trip due to a perceived emergency. There is currently no industry consensus on the proper balance between ADS passenger agency and the potential for introducing unexpected outcomes in dynamic traffic environments. In order to build public trust in automated vehicles, passengers should be given an option to exercise some type of control (agency) to intervene during situations they perceive as emergencies. Passenger-initiated emergency trip interruption features — however they manifest in a given vehicle — can help establish this confidence in ADS technologies.

 

SCOPE

AVSC Best Practice for Passenger-Initiated Emergency Trip Interruption recommends processes surrounding aspects of passenger-initiated features in SAE level 4 and 5 fleet-managed ADS-DVs. It recommends criteria and processes for passenger initiation of these features from inside the vehicle; communication with passengers and fleet operations; enhanced diagnoses of the situation; interaction outside the vehicle with other road users; and general post-stop actions. These recommendations apply to commercially available, deployed ADS-DVs providing trips to people.

The Best Practice addresses precautions against some types of foreseeable misuse. However, neither an ADS nor a passenger-initiated emergency feature can be expected to determine the veracity of an emergency. It is recommended to assume an emergency is taking place even if the objective reality of the situation in question turns out not to warrant such a designation. Determining the validity of a passenger’s perception of an emergency or arbitrating what passengers consider an emergency is outside the scope of this best practice.

It was developed with fleet-managed, SAE Level 4 vehicles in mind — i.e. vehicles requiring no human intervention to operate within their ODD.  These vehicles are NOT privately owned.

 

TYPOLOGY

The Best Practice identifies and classifies trip interruptions. Trip interruptions are grouped into those initiated by the ADS and those initiated by passengers, then subdivided into emergency and non-emergency interruptions.

Two types of passenger-initiated emergency trip interruption features are classified: passenger-initiated emergency stop (PES) and passenger-initiated emergency call (PEC).

The AVSC recommends that every fleet-managed SAE level 4 and 5 ADS-DV be equipped with a PES or PEC or both.

 

UNIQUE ATTRIBUTES AND CONSIDERATIONS

This section outlines the differing processes of PES and PEC features. Crucially, an emergency stop feature will always stop the vehicle, while an emergency call feature will always connect with a human call-taker. In the case of PEC, the call-taker may initiate a stop may re-route the vehicle — to a safe location or hospital, for example — or may be able to resolve the perceived emergency without further action. Conceptual process flow charts visualize recommended PES and PEC functionalities and recommended outcomes.

ADS-DVs equipped with a PEC must have humans available to field calls whenever passengers are on board the vehicle. The document also outlines minimum levels of information that should be made available to PEC call takers, such as vehicle location, status, and visual information from inside the cabin.

 

COMMON ATTRIBUTES AND CONSIDERATIONS

PES and PEC features share key common traits (e.g. indicating use for emergency only) but must be clearly distinguishable from one another and distinguishable from non-emergency trip interruption features. When activated, they should elicit an immediate and predictable response.

Both features should be:

• Easily recognizable
• Reasonably accessible
• Always available

Considerations are provided for mitigating potential foreseeable misuse and abuse. These center on education and making information readily available to help establish expectations and develop social norms.

The best practice outlines communication and human-machine-interaction recommendations for both PES and PEC features, including:

• Initiation acknowledgment
• Enhanced diagnosis and interior illumination
• Interactions with other road users
• Communications to fleet operations

Following a PES, and if a PEC results in the vehicle stopping, recommendations for post-stop actions are given. These include alerting passengers that emergency stop actions have been completed, maintaining certain vehicle functions, and requiring fleet operations authorization to restart the trip.