Automated vehicles have captured the public’s imagination in recent years following successful on-road demonstrations by developers such as Google. The prospect of enjoying the benefits of personal mobility without the traditional responsibilities of driving has led to overly broad claims in the popular press based on scant information about the technology and its potential uses. One writer recently suggested that automated vehicles should be banned because they allegedly threaten public transit and the environment, while another argued that automated vehicles should be mandated within a few years because they promise substantial safety benefits over traditional driving. These extreme examples indicate the range of uninformed opinion that plagues much of the public debate on road vehicle automation.
However, some scholars have taken a systematic approach to the technology and its applications, developing inventories of potential problems and working to address them. In the legal realm, one key development was the publication of a 2012 paper by Bryant Walker Smith, law professor at the University of South Carolina and chair of the Transportation Research Board’s Standing Committee on Emerging Technology Law at the National Academies. Smith concluded that in most U.S. jurisdictions, automated vehicles are not explicitly prohibited by current laws, although he highlighted several potential conflicts in state motor vehicle codes that may preclude certain operations. One problem he identified is states’ following-too-closely (FTC) statutes, which outlaw many automated vehicle platooning applications.
Automated vehicle platooning—often referred to as road trains, connected automated vehicles, or cooperative automated vehicles—is one of the more promising potential functions of automated vehicle technology. Platooned vehicles can travel closer together at highway speeds, mitigating traffic congestion, improving fuel economy, and increasing vehicle throughput without costly roadway capacity expansions. In the freight sector, trucking companies are eager to move their goods with fewer workers, in order to both address the chronic shortage of qualified commercial drivers and permanently reduce labor costs.
With the coming advent of automated vehicles, numerous sections of state motor vehicle codes likely will need revision if we are to take advantage of the full range of benefits offered by vehicle automation technology.
Authorizing automated vehicle platoons in each jurisdiction merely requires exempting automated vehicle platoons from existing follow-to-closely rules.
State FTC rules vary by vehicle class and rule type. Most class-specific FTC rules are contained within a single statutory section. The three vehicle classes are:
- Cars (including light-duty trucks);
- Heavy trucks; and
- Caravans (sometimes called motorcades).
The four FTC rule types are:
- “Reasonable and prudent;”
- Distance; and
- “Sufficient space to enter and occupy without danger.”
A “reasonable and prudent” rule requires a vehicle operator to follow the vehicle in front of her while allowing for sufficient space to stop in an emergency. In application, this is a subjective standard that grants law enforcement a large degree of leeway. It is the most common FTC rule for cars and is sometimes combined with other types of rules.
Time-based FTC rules specify the time interval between vehicles, such as by forbidding drivers from following less than “at least two seconds behind the vehicle being followed.” This is the least common rule type and is limited to just two jurisdictions, Alaska and Utah.
Distance rules specify the precise safe following distance either by codifying a fixed distance interval or, in the case of Alabama, a proportional distance interval requiring that “the driver of a vehicle shall leave a distance of at least 20 feet for each 10 miles per hour of speed between the vehicle that he or she is driving and the vehicle that he or she is following.” This rule type is most common among the heavy truck and caravan vehicle classes.
The “sufficient space to enter and occupy without danger” rule, which is most common among the heavy truck and caravan vehicle classes, aims to allow other road users to pass other vehicles safely and enter and exit the roadway.
A few U.S. jurisdictions lack explicit FTC rules, relying instead on broader reckless driving statutes. A number of jurisdictions do not fully define all vehicle classes, which means the “car” class becomes the default rule for all vehicles. Further, some jurisdictions distinguish between road types. A few jurisdictions have functionally identical rule types featuring different terminology, but these are rare exceptions.
Exempting automated vehicle platoons from existing FTC rules is slightly more complicated in some jurisdictions, such as those in which FTC rules are spread through two or three class-specific statutory sections. For example, California’s FTC rules are divided into three separate statutory sections for cars, heavy trucks, and caravans. In addition, two jurisdictions, Alaska and Massachusetts, codify their FTC rules within administrative, rather than statutory codes.
Utah was the first state to exempt and authorize the testing of connective vehicles in 2015. Florida followed suit in early 2016. Beginning in 2017, Arkansas, Georgia, North Carolina, South Carolina, Tennessee, and Texas have enacted FTC rule exemptions allowing for commercial platooning, and several other jurisdictions are considering similar reforms.
This handbook, an update of the 2016 edition, provides a comprehensive national overview of FTC statutes and regulations and recommends specific changes for each jurisdiction.
It presents two model amendments for each jurisdiction. The first, the “strong amendment,” is self-executing and would preclude the state from promulgating any regulations restricting automated vehicle platoons. This is the most liberal, strongly pro-market method of authorizing automated vehicle platooning. The second, the “weak amendment,” would require agency implementation and grant state motor vehicle authorities discretion in how they promulgate platooning FTC rules, while providing a statutory backstop aimed at preventing excessively burdensome regulation.
From a pro-market perspective, the strong amendment offers the greatest protections against potential burdensome regulations. However, some legislatures may prefer to authorize platooning under a regulated rollout and thus prefer the weak amendment. In the latter case, lawmakers who opt for agency action will need to examine what additional agency resources may be required to carry out the weak amendment’s administrative mandate.
Finally, readers should note that this report is based upon an inventory of state laws as published rather than as interpreted by the courts. A legal analysis of that type is beyond the scope of this report.
 Google, “Google Self-Driving Car Project,” Google website, https://www.google.com/selfdrivingcar/.
 Rebecca Solnit, “We don’t need self-driving cars—we need to ditch our vehicles entirely,” The Guardian, April 6, 2016, http://www.theguardian.com/commentisfree/2016/apr/06/self-driving-cars-public-transportation.
 Kevin Roose, “Driving should be illegal,” Fusion, October 5, 2015,
 Bryant Walker Smith, “How Governments Can Promote Automated Driving,” working paper, March 17, 2016, http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2749375.
 Smith, Automated Vehicles Are Probably Legal in the United States (Stanford, California: Center for Internet and Society) November 1, 2012, http://cyberlaw.stanford.edu/publications/automated-vehicles-are-probably-legal-united-states.
 European Automobile Manufacturers Association, “What are the benefits of truck platooning?” EAMA website, March 10, 2016, http://www.acea.be/news/article/what-are-the-benefits-of-truck-platooning.
 Alaska Admin. Code tit. 13, § 02.090(a).
 Ala. Code § 32-5A-89(a).
 Utah Code § 41-6a-711(2)(b).
 Fla. Stat. § 316.0896.