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Defining “Drivers” in the Driverless Age

By Alexandra Ladwig*

In 2016, Google wrote to the National Highway Traffic Safety Administration (NHTSA), the federal agency tasked with setting federal traffic safety standards and monitoring compliance,[1] asking for an interpretation of the word “driver” as it related to Google’s proposed designs for an autonomous vehicle.[2] Google and other autonomous vehicle manufacturers are rightfully concerned, as the definition of “driver” will be important for determining safety standards and monitoring compliance, which falls within the domain of the federal government (specifically, NHTSA).[3] The definition of “driver” will also be important for determining tort liability, which falls within the domain of state governments, as state governments control insurance and liability.[4] Basically, the federal government has control over vehicles and state governments have control over human drivers.[5] While potential regulatory issues concerning autonomous vehicles (AVs) abound, this blog will focus generally on two things: (1) The ways in which the federal and state definitions of “driver” are currently developing with regard to autonomous vehicles, and (2) Under which circumstances a federal definition may preempt that of a state.

States regulate human drivers. They have authority over licensing, insurance, and tort liability.[6] Their main concern thus lies with how to define “driver” and “operator” in relation to licensing requirements and tort liability.[7] So far, twenty-one states have passed legislation related to autonomous vehicles.[8] There is an extreme variance between these twenty-one states on how, if at all, they choose to define “drivers” with regard to AVs. On one end of the spectrum are states like Michigan, which does not define the term “operator” or “driver” for the purposes of its AV legislation or for the purposes of liability generally.[9] This presumably gives flexibility to autonomous vehicle manufacturers in testing their designs, as they do not have to comply with specific driver regulations.[10] On the other end of the spectrum are states like Tennessee, which offers a clear definition. Recently enacted Tennessee legislation defines “driver” as “the ADS [Automated Driving System] when the ADS is engaged” and offers the same definition for the word “operator”. [11]

The federal government regulates highway safety. NHTSA, an agency within the Department of Transportation (DOT), is the federal agency tasked with regulating and monitoring compliance with federal safety standards[12], and has assumed control of the regulatory sphere for defining AV safety.[13] NHTSA sets Federal Motor Vehicle Safety Standards (FMVSSs) for new motor vehicles and motor vehicle equipment, and compliance with the relevant FMVSSs must be certified by manufacturers before they can sell their vehicles.[14] The current federal definition of “driver” comes from Section 571.3 of the National Traffic and Motor Vehicle Safety Act of 1966(49 CFR 571.3), from which NHSTA derives its authority to regulate federal traffic safety.[15] Section 571.3 defines “driver” as “the occupant of a motor vehicle seated immediately behind the steering control system”, and NHTSA uses this definition in issuing and interpreting its FMVSSs.[16] NHTSA’s 2016 letter of interpretation to Google noted that it will interpret “driver” in the context of Google’s proposed motor vehicle design as being the Self-Driving System (SDS) for the purpose of FMVSSs compliance, although it noted that Google will still have to apply for several exemptions to be fully in compliance with all relevant FMVSSs.[17] The NHTSA further mentioned in its letter that it would consider a future rulemaking process to update its interpretation of the definition of “driver” under Section 571.3.[18]

In their letter of interpretation to Google, the NHTSA essentially agreed that Google’s definition of “driver” for the company’s proposed self-driving vehicle design was indeed acceptable under current NHTSA regulations, while leaving room for the federal government to change its mind.[19] NHTSA made clear that its letter of interpretation in response to Google’s request applied only to Google’s proposed design, and that Google would still have to request exemptions to several of NHTSA’s Federal Motor Vehicle Safety Standards (FMVSSs) that would be impossible for non-human driven cars to meet under the way “driver” is currently defined.[20] Additionally, while NHTSA has regulatory authority over federal highway safety standards, Google and other AV manufacturers will have to comply with various state safety standards and their definitions of “driver”.[21]

The question remains whether states would have to adopt a federal definition of the term “driver” in their own safety laws or even in their liability and licensing laws. Both states and the federal government have an incentive to develop a consistent definition of the term, as compliance with federal safety standards acts as a defense to tort liability claims brought against vehicle manufacturers under state law.[22] If NHTSA does indeed pursue a rulemaking process, courts will give deference to its interpretation of the word “driver” as applied to AVs in lieu of any other federal legislation on the topic.[23] Any federal standard set by the NHTSA with regard to safety will likely also preempt state law involving a safety standard for tort liability claims.[24]

Amidst NHTSA’s hinted-at rulemaking, Congress is currently in the process of passing comprehensive AV legislation itself.[25] As determined by the Supreme Court in Michigan Canners & Freezers Association v. Agricultural Marketing & Bargaining Board, such federal law may preempt existing state laws if 1) Congress explicitly sates that it intends for its legislation to preempt state laws, 2) Congress “indicate[s] an intent to occupy an entire field of regulation”, or 3) State law conflicts with federal law.[26] States are already required to maintain traffic safety standards at a level comparable to those set by NHTSA,[27] so states will at least be required to follow any official NHTSA interpretation of the word “driver” or “operator” as it relates to safety standards. The AV legislation package recently passed by the House does not include definitions for either term,[28] so for the near future it is likely that states will be bound only by NHTSA safety standards in determining how to define the words “driver” and “operator” within their jurisdiction.

On September 12, 2017, the DOT released its latest AV guidelines.[29] These purely voluntary guidelines again emphasize the authority of the federal government in determining safety standards and motor vehicle regulation, while regulation of human drivers is the domain of the States.[30] The guidelines express a desire for consistency between jurisdictions on AV regulations and encourage cooperation among States, localities, and the federal government in setting standards for AVs. Most importantly, however, the guidelines re-emphasize the federal government’s “hands-off” approach to AV innovation.[31] The guidance encourages states to “review traffic laws and regulations that may serve as barriers to operation of [AV]s”[32], and stresses the need for NHTSA to have sole authority over AV development, as “allowing NHTSA alone to regulate the safety design and performance aspects of [AV] technology will help avoid conflicting Federal and State laws and regulations that could impede development”.[33]

It remains uncertain whether states will come to a consensus on how to define operators and drivers in the age of autonomous vehicles, but due to a myriad of potential economic benefits that come from allowing AV development in their state and the level of deference afforded to federal safety regulations, states have an incentive to follow the NHTSA’s advice and coordinate with the federal government’s definition of “driver” to adapt laws that “promote innovation and the swift, widespread, safe integration of [AV]s”.[34]

*Alexandra Ladwig is a Junior Editor on MJEAL. She can be reached at

The views and opinions expressed in this blog are those of the authors only and do not reflect the official policy or position of the Michigan Journal of Environmental and Administrative Law or the University of Michigan.

[1] NHTSA Response Letter to Google Request for Interpretation,–%20compiled%20response%20to%2012%20Nov%20%2015%20interp%20request%20–%204%20Feb%2016%20final.htm

[2] Id.

[3] Automated Driving Systems: A Vision for Safety, US Department of Transportation (September 2016), (

[4] Id.

[5] Id.

[6] Id.

[7]  Geistfeld, Mark, A Roadmap for Autonomous Vehicles: State Tort Liability, Automobile Insurance, and Federal Safety Regulation (November 1, 2017). California Law Review, Forthcoming; NYU School of Law, Public Law Research Paper No. 17-09. Available at SSRN:

[8] National Conference of State Legislatures, Autonomous Vehicles (October 2017),

[9] 2016 Mich. Pub. Acts 332

Click to access 2016-PA-0332.pdf

[10] Id.

[11] 2017 Tennessee SB 151

[12] Automated Driving Systems: A Vision for Safety, US Department of Transportation (September 2016),

[13] Id.

[14] Id.

[15] National Traffic and Motor Vehicle Safety Act of 1966, (1966),

[16] Id.

[17] NHTSA Response Letter to Google Request for Interpretation,–%20compiled%20response%20to%2012%20Nov%20%2015%20interp%20request%20–%204%20Feb%2016%20final.htm

[18] Id.

[19] Id.

[20] Id.

[21] Id.

[22] See Geistfeld, supra note 7.

[23] See Chevron U.S.A., Inc. v. Natural Resources Defense Council, 467 U.S. 837, (1984)

[24] See Geier v. American Honda Motor Co., Inc., 529 U.S. 861, (2000)

[25] “Congress Unites (Gasp) to Spread Self-Driving Cars Across America”, (September 2017),

[26] Mich. Canners & Freezers Ass’n v. Agric. Mktg. & Bargaining Bd., 467 U.S. 461, 469, 478 (1984)

[27] Automated Driving Systems: A Vision for Safety, US Department of Transportation (September 2016),

[28] Safely Ensuring Lives Future Deployment and Research In Vehicle Evolution Act, H.R. 3388, (2017),

[29] Automated Driving Systems: A Vision for Safety, US Department of Transportation (September 2016),

[30] Id.

[31] Id.

[32] Id.

[33] Id.

[34] Id.

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