The US Department of Transportation’s National Highway Traffic Safety Administration (NHTSA) issued a preliminary policy statement concerning vehicle automation, including its plans for research on related safety issues and recommendations for states related to the testing, licensing, and regulation of “autonomous” or “self-driving” vehicles.
Self-driving vehicles are those in which operation of the vehicle occurs without direct driver input to control the steering, acceleration, and braking and are designed so that the driver is not expected to constantly monitor the roadway while operating in self-driving mode.
NHTSA’s policy addresses:
An explanation of the many areas of vehicle innovation and types of automation that offer significant potential for enormous reductions in highway crashes and deaths;
A summary of the research NHTSA has planned or has begun to help ensure that all safety issues related to vehicle automation are explored and addressed; and
Recommendations to states that have authorized operation of self-driving vehicles, for test purposes, on how best to ensure safe operation as these new concepts are being tested on highways.
Several states, including Nevada, California and Florida have enacted legislation that expressly permits operation of autonomous vehicles under certain conditions. These experimental vehicles are at the highest end of a wide range of automation that begins with some safety features already in vehicles, such as electronic stability control.
The new policy will provide states interested in passing similar laws with assistance to ensure that their legislation does not inadvertently impact current vehicle technology and that the testing of self-driving vehicles is conducted safely.
The policy statement also describes NHTSA’s research efforts related to autonomous vehicles. While the technology remains in early stages, NHTSA is conducting research on self-driving vehicles so that the agency has the tools to establish standards for these vehicles, should the vehicles become commercially available. The first phase of this research is expected to be completed within the next four years.
Levels of automation. NHTSA defines vehicle automation as having five levels:
No-Automation (Level 0): The driver is in complete and sole control of the primary vehicle controls—brake, steering, throttle, and motive power—at all times.
Function-specific Automation (Level 1): Automation at this level involves one or more specific control functions. Examples include electronic stability control (ESC) or pre-charged brakes, where the vehicle automatically assists with braking to enable the driver to regain control of the vehicle or stop faster than possible by acting alone.
Combined Function Automation (Level 2): This level involves automation of at least two primary control functions designed to work in unison to relieve the driver of control of those functions. An example of combined functions enabling a Level 2 system is adaptive cruise control in combination with lane centering.
Limited Self-Driving Automation (Level 3): Vehicles at this level of automation enable the driver to cede full control of all safety-critical functions under certain traffic or environmental conditions and in those conditions to rely heavily on the vehicle to monitor for changes in those conditions requiring transition back to driver control. The driver is expected to be available for occasional control, but with sufficiently comfortable transition time. The Google car is an example of limited self-driving automation.
Full Self-Driving Automation (Level 4): The vehicle is designed to perform all safety-critical driving functions and monitor roadway conditions for an entire trip. Such a design anticipates that the driver will provide destination or navigation input, but is not expected to be available for control at any time during the trip. This includes both occupied and unoccupied vehicles.
NHTSA’s research. NHTSA research on automated vehicles has already led to regulatory and other policy developments. For example, the agency developed and issued a standard that made that Level 1 technology mandatory on all new light vehicles since MY 2011. More recently, NHTSA issued a proposal that would require ESC on heavy vehicles.
We are currently engaged in extensive research on automatic braking technologies (dynamic brake support and crash imminent braking), which can be considered Level 1 technologies. Within the next year, the agency will make a determination on whether either or both of these two automatic braking technologies should be considered for rulemaking or for inclusion within the NCAP program. Our current work involves development of test procedures and assessment of benefits for these Level 1 technologies. Of course, we are also working very hard on V2V communications technology, which may offer significant crash reduction benefits on its own or when coupled with on-board warning and automated control systems.
As we continue our work on Level 1 automation and our efforts to calculate the safety benefits that those single-function systems may offer in the near term, we have begun or are planning research on Levels 2 through 4 automation as well. NHTSA is working cooperatively with other DOT agencies on this research, given its relevance to the intermodal intelligent transportation systems program. Initially, the agency has identified three key areas where it has begun or plans to conduct research for these more advanced automated vehicle systems. These areas are human factors research, development of system performance requirements, and addressing electronic control system safety.—“Preliminary Statement of Policy”
Recommendations concerning state activities related to self-driving vehicles. NHTSA’s recommendations to states supporting operation of “autonomous” vehicles are tailored to Levels 3 and 4 automation.
Because further research is needed to fully understand the technical and human factors issues implicated by autonomous vehicles, NHTSA’s guidance is provisional and subject to reconsideration and revision as appropriate, especially before any potential regulatory action, the agency cautioned.
The agency is not aware of any systems intended for wide scale deployment currently under development for use in motor vehicles that are capable of Level 4 automation. As we stated previously, very few Level 3 automated systems exist and the systems that do exist are still at the earlier stages of testing/development. Because Level 4 automated systems are not yet in existence and the technical specifications for Level 3 automated systems are still in flux, the agency believes that regulation of the technical performance of automated vehicles is premature at this time. While NHTSA’s authority, expertise, and mandate is to establish uniform, national standards needed for vehicle safety, the agency recognizes that premature regulation can run the risk of putting the brakes on the evolution toward increasingly better vehicle safety technologies.
While the agency does not believe that self-driving vehicles are currently ready to be driven on public roads for purposes other than testing, the agency would like to emphasize that it is encouraged by innovations in automated driving and their potential to transform our roadways. The agency is confident that the development and testing of Level 3 automated systems will provide answers to many of the technical and human factors questions presented by the technology.—“Preliminary Statement of Policy”
NHTSA’s recommendations include:
Ensure that the driver understands how to operate a self-driving vehicle safely.
Ensure that on-road testing of self-driving vehicles minimizes risks to other road users.
Limit testing operations to roadway, traffic and environmental conditions suitable for the capabilities of the tested self-driving vehicles.
Establish reporting requirements to monitor the performance of self-driving technology during testing.
Ensure that the process for transitioning from self-driving mode to driver control is safe, simple, and timely.
Self-driving test vehicles should have the capability of detecting, recording, and informing the driver that the system of automated technologies has malfunctioned.
Ensure that installation and operation of any self-driving vehicle technologies does not disable any federally required safety features or systems.
Ensure that self-driving test vehicles record information about the status of the automated control technologies in the event of a crash or loss of vehicle control.
NHTSA does not recommend that states authorize the operation of self-driving vehicles for purposes other than testing at this time. We believe there are a number of technological issues as well as human performance issues that must be addressed before self-driving vehicles can be made widely available. Self-driving vehicle technology is not yet at the stage of sophistication or demonstrated safety capability that it should be authorized for use by members of the public for general driving purposes. Should a state nevertheless decide to permit such non-testing operation of self-driving vehicles, at a minimum the state should require that a properly licensed driver (i.e., one licensed to drive self-driving vehicles) be seated in the driver’s seat and be available at all times in order to operate the vehicle in situations in which the automated technology is not able to safely control the vehicle. As innovation in this area continues and the maturity of self-driving technology increases, we will reconsider our present position on this issue.—“Preliminary Statement of Policy”