How Do Self-Driving Cars Work?

Self-driving cars use an array of sensors and control systems to automate the process of driving. Some are more automated than others, but most self-driving cars allow for the manual takeover of controls. Self-driving cars build on technologies that have been on the road for years. Examples of these technologies include adaptive cruise control, lane-keeping assistance, and automated braking. The technologies behind self-driving cars are referred to as advanced driver assistance systems (ADAS). The intent behind building these systems is to reduce human error while driving, which is responsible for at least 90 percent of vehicle crashes or accidents in the U.S. Early iterations, such as the Tesla Autopilot, have been designed to fall back on a human driver in the case of emergencies. Some states only allow self-driving vehicles to operate on public roads with a human operator or safety driver inside. Other states allow fully autonomous vehicles to operate with no human inside.

When tech companies started experimenting with self-driving cars, they experimented on private property, so there were no public use laws that could deter them. Few laws existed relating to self-driving technology because the idea was mostly limited to science-fiction. In recent years, with the technology reaching a more advanced stage, states have passed legislation to regulate or authorize the testing or deployment of self-driving cars on public roads. To date, no state has explicitly prohibited or outlawed self-driving cars. In 2018, congress introduced a bill that would create a baseline for the testing and operation of self-driving vehicles, but it is yet to be voted on. At the federal level, the only rules around automated vehicles are not rules but guidelines made by the National Highway Traffic Safety Administration. The National Conference of State Legislatures created a tool to track or research legislation related to autonomous vehicles.

States That Explicitly Allow Self-Driving Cars to Be Deployed on Public Roads

The following states have explicitly legalized the deployment of self-driving cars on public rods—either through legislation or executive order: Alabama, Arizona, Arkansas, California, Colorado, Connecticut, Delaware, District of Columbia, Florida, Georgia, Hawaii, Idaho, Illinois, Indiana, Iowa, Kentucky, Louisiana, Maine, Massachusetts, Michigan, Minnesota, Mississippi, Nebraska, Nevada, New Hampshire, New York, North Carolina, North Dakota, Ohio, Oklahoma, Oregon, Pennsylvania, South Carolina, South Dakota, Tennessee, Texas, Utah, Vermont, Virginia, Washington, Wisconsin.

States That Require All Deployed Self-Driving Cars to Have a Human Operator in the Vehicle

As of 2021, Connecticut, District of Columbia, Illinois, Massachusetts, New Hampshire, New York, and Vermont require a human operator in the vehicle. Some states (Florida, Georgia, Nebraska, Nevada, North Carolina, North Dakota, Pennsylvania, and Washington) condition the need for a human operator to be present based on the level of the vehicle’s automation.

States With No Self-Driving Car Laws or Executive Orders

These states have not passed any laws or executive orders pertaining to autonomous vehicles: Alaska, Kansas, Maryland, Missouri, Montana, New Jersey, New Mexico, Rhode Island, West Virginia, Wyoming.

Alabama

Alabama passed legislation defining automated driving systems. Law SB 47 authorizes commercial self-driving vehicles to operate in the state without a driver physically present, so long as certain criteria have been met.

Alaska

Alaska has no legislation regarding self-driving cars, and no governor of the state has issued an executive order regarding self-driving cars. That means there are no laws on the books to prevent self-driving cars, but the state has not explicitly allowed them either.

Arizona

Arizona was one of the first test sites for self-driving cars. This was enabled by an executive order that set guidelines for testing and operating self-driving cars. It also instructed state agencies to eliminate potential hurdles for companies looking to test driverless technologies. The Governor of Arizona ordered Uber to suspend all self-driving car tests in the state, following a fatal accident in 2018.

Arkansas

Arkansas has legislation that allows the operation of self-driving vehicles. Law HB 1561 allows for the operation of self-driving and fully autonomous vehicles in the state under an autonomous vehicle pilot program approved by the State Highway Commission.

California

California was one of the first states to explicitly allow, and encourage, the development of self-driving technology after several companies began small-scale experimentation on private property in the state. Bill 1298, passed in 2012, established the first procedures for testing self-driving cars in the state. Laws passed since then regulate the rights of law enforcement to seize improperly licensed self-driving cars, the ability of local municipalities to charge specific taxes on driverless taxi services, and other administrative permissions.

Colorado

In 2017, Colorado passed SB 213, which sets legal definitions for automated driving systems and explicitly allows people to use self-driving cars, provided that such vehicles comply with both state and federal laws.

Connecticut

Connecticut has legislation that defines terms related to self-driving cars and establishes procedures for testing self-driving cars in four municipalities in the state. The law (SB 260) and its amendments (SB 924) require an operator to be physically present in any automated vehicle while in operation.

Delaware

Delaware has no self-driving car legislation. In 2017, the governor signed an executive order establishing an advisory council on self-driving cars. There are no specific laws on the books to prohibit self-driving cars.

Florida

Florida passed legislation in 2012 (HB 1207) to encourage the safe testing of self-driving car technology in the state. The legislation also explicitly stated that Florida does not prohibit the testing or operation of self-driving cars. Legislation passed in 2016 (HB 7027) permits the operation of autonomous vehicles with no driver present in the vehicle.

Georgia

Georgia has legislation (SB 219) that defines automated driving systems and exempts the operators of self-driving cars from the requirement to have a valid driver’s license. The legislation also sets forth the requirements for a self-driving vehicle to operate in the state without a human operator present in the vehicle.

Hawaii

Hawaii has no self-driving car legislation, but the governor has enacted an executive order pertaining to self-driving cars. The order instructs government agencies in the state to work with interested companies to facilitate the testing of self-driving vehicles in Hawaii.

Idaho

Idaho has no self-driving car legislation. In 2018, the governor signed an executive order supporting the development of regulations related to the testing of self-driving vehicles in the state. There are no laws that specifically prohibit self-driving cars.

Illinois

Illinois does not have any self-driving car laws on the books. However, the governor signed an executive order in 2018 that established an initiative to promote the development and testing of self-driving cars in the state. In 2017 the state passed a law (HB 791) prohibiting local authorities from enacting or enforcing rules that limit or ban the use of automated vehicles.

Indiana

Indiana doesn’t have any self-driving car laws on the books that pertain to personal vehicles. The state’s only self-driving vehicle law (HB 1290) addresses the electronically coordinated platooning of autonomous vehicles. It also outlines a system for approving the use of such vehicles.

Iowa

In 2019, Iowa passed SF 302, which defines self-driving vehicles and permits these vehicles to operate in the state without a human operator as long as the vehicles meet a set of conditions.

Kansas

There are no self-driving vehicle laws on the books in Kansas, and there have been no executive orders. There are no laws pertaining to self-driving vehicles at all, so they are not specifically prohibited.

Kentucky

Kentucky has a law (SB 116) regulating autonomous platoons of commercial vehicles. There are no laws on the books relating to non-commercial self-driving cars. Self-driving cars are not specifically prohibited by law.

Louisiana

Louisiana has a law (HB 1143) that defines autonomous technology in relation to self-driving vehicles, and a law (HB 308) that sets regulations for platoons of autonomous commercial vehicles. In 2019, the state passed a law (HB 455), which permits the use of automated vehicles to operate in the state without a human driver present in the vehicle.

Maine

The governor of Maine signed an executive order to create an advisory committee to facilitate the testing and operation of self-driving vehicles in the state. Additionally, legislation was passed in 2018 (HP 1204) to codify the responsibilities of that committee and to create a roadmap for the development of self-driving technology in Maine.

Maryland

There are no self-driving vehicle laws in Maryland, and there have been no executive orders pertaining to self-driving vehicles. There are no laws on the books that specifically forbid self-driving vehicles.

Massachusetts

There are no self-driving vehicle laws in Massachusetts. In 2016 the governor issued an executive order to facilitate the testing and operation of self-driving cars in the state. There are no laws that specifically prohibit self-driving vehicles.

Michigan

Michigan has several laws pertaining to self-driving vehicles. SB 995 officially permits the use of autonomous vehicles under certain conditions. SB 996 creates provisions for the operation of autonomous vehicles without the presence of a human operator.

Minnesota

In 2019, Minnesota passed HB 6, which allows autonomous vehicle operators to apply for permission to use a platooning system of self-driving vehicles. Beyond the use of autonomous platoons, the state has no law governing the use of independent self-driving vehicles. In 2018 the governor signed an executive order aimed at facilitating the testing of self-driving cars in the state.

Mississippi

There are no laws in Mississippi that address non-commercial self-driving cars. The only law (HB 1343) that pertains to autonomous vehicles specifically relates to platoons of autonomous commercial vehicles. There are no laws that specifically prohibit self-driving vehicles.

Missouri

There are no laws in Missouri that pertain to self-driving vehicles, so self-driving cars are not explicitly prohibited in the state.

Montana

Montana doesn’t have any laws that pertain to self-driving vehicles, and there have been no related executive orders. Since self-driving cars have never been specifically addressed, they are not explicitly prohibited in the state.

Nebraska

Nebraska has a law (LB 989) that defines automated driving systems and sets requirements that self-driving cars in the state must meet. The vehicle must have fail-safe systems, must obey all traffic laws, and the operator is required to demonstrate financial responsibility in the form of adequate insurance or self-insurance.

Nevada

Nevada was the first state in the country to enact legislation to make it easier for companies to develop and test self-driving vehicles in the state. The first bill in 2011 (AB 511) created a driver’s license endorsement for the operation of self-driving vehicles. Another bill (SB 140) specifically allows the operator of a self-driving vehicle to use a cellphone while driving, which is illegal for drivers of regular vehicles in the state. Other laws passed since then (SB 313 and AB 69) specify conditions and definitions for self-driving vehicles and automated platoons.

New Hampshire

In 2019, New Hampshire passed SB 216, which directs the department of safety to establish a pilot program that would test self-driving vehicles on public roads in the state.

New Jersey

In 2019, New Jersey passed a law (AJR 164) to establish a task force charged with studying autonomous vehicles and to provide a set of recommendations for laws and regulations governing their use in the state.

New Mexico

There are no self-driving vehicle laws on the books in New Mexico, and there have been no executive orders issued. Self-driving vehicles are not specifically prohibited by law.

New York

New York has legislation (SB 2005) that sets out testing requirements and procedures for self-driving vehicles in the state. Additional legislation (AB 9508) has created test procedures and instructions for first responders on how to deal with autonomous vehicles.

North Carolina

North Carolina has legislation (HB 469) that establishes regulations for self-driving vehicles. The legislation specifies that fully autonomous vehicles can be operated without a driver’s license. Additionally, no child aged 12 years or younger may ride in an autonomous vehicle without an adult present.

North Dakota

North Dakota has self-driving vehicle legislation (HB 1065 and HB 1202) that requires the state department of transportation to study autonomous vehicles. In 2019, the state passed legislation (HB 1199 and HB 1418) defining autonomous vehicle platoons, while also directing the department of transportation to develop a plan that would provide guidelines for the use of such platoons in the state.

Ohio

There are no laws on the books in Ohio that relate to self-driving vehicles. Two relevant executive orders have been signed by the governor. The first created an organization to help self-driving car companies interface with the state government. The second created regulations for testing self-driving vehicles in the state.

Oklahoma

In 2019, Oklahoma passed a law (SB 189) that defines autonomous vehicle platoons and exempts non-lead vehicles in a platoon from state traffic laws regarding mandatory distances between vehicles in motion. A separate law (SB 365) asserts that only the state government may pass laws or rules governing the operation of self-driving cars in Oklahoma.

Oregon

Oregon has legislation (HB 4063) that establishes an autonomous vehicle task force. This task force is responsible for developing recommendations for policies governing the use of self-driving cars in the state. Oregon has no laws banning or limiting the use of autonomous vehicles.

Pennsylvania

There have been two laws passed that relate to autonomous vehicles, including one to allocate funds for autonomous vehicle technology (SB 1267), and one that sets definitions for platoons of autonomous commercial vehicles (HB 1958). There are no laws that specifically prohibit self-driving cars.

Rhode Island

There are no self-driving car laws in Rhode Island, and there have been no relevant executive orders. Self-driving vehicles are not specifically prohibited by law.

South Carolina

There are no self-driving car laws on the books in South Carolina, and there have been no relevant executive orders. The only relevant law pertains to the minimum following distance allowed by platoons of autonomous vehicles. Self-driving vehicles are not specifically prohibited by law.

South Dakota

In 2019, South Dakota passed a law (HB 1068) directing the state transportation commission to publicize rules regarding the use of autonomous vehicle platoons. Other than this law, there are no rules that expressly forbid the use of automated vehicles in the state.

Tennessee

Tennessee has several laws relating to self-driving cars, including one that prevents local governments from banning autonomous vehicles (SB 598). Other laws (SB 2333, SB 1561, and SB 151) define various autonomous vehicle terms and specifically allow the use of self-driving vehicles if certain conditions are met.

Texas

Texas has legislation (SB 2205) that defines a variety of autonomous vehicle terms and explicitly states that self-driving vehicles are legal in the state. The legislation also prevents local governments from outlawing self-driving vehicles and provides for the operation of fully autonomous vehicles, with no human operator, under specific circumstances.

Utah

Utah has passed laws to authorize and require studies of autonomous vehicle technologies in the state (HB 373 and HB 280). In 2019, the state passed a law (HB 101) that allows for the operation of autonomous vehicles on state highways under certain conditions: The vehicle must be properly titled, registered, and insured, along with requirements for the operator. The law also authorizes the Department of Commerce to revoke the registration of a self-driving vehicle and establishes a series of technical safety rules for autonomous vehicles operating in the state.

Vermont

Vermont has passed legislation (HB 494) to require the state department of transportation to convene meetings regarding autonomous vehicles and report to the House and Senate committees to provide recommendations. In 2019, the state passed a law (SB 149) that prohibits the testing of self-driving vehicles on public, state, or town highways until the state traffic committee approves a permit application for automated vehicle testing in the state. The law also establishes definitions and authorities for the approval of permits.

Virginia

The only law in Virginia that pertains to self-driving vehicles (HB 454) allows operators of such vehicles to view visual displays while the vehicle is under autonomous operation. This is contrasted with regular vehicles, which can only have visual displays if the display shuts down when the vehicle is in motion.

Washington

In 2017, the governor of Washington issued an executive order to address autonomous vehicle testing in the state. There is also a law (HB 2970) that directs the state transportation commission to develop policies to govern self-driving vehicles. There are no laws prohibiting self-driving vehicles.

Washington, D.C.

Legislation passed by the Washington, D.C. council (DC B 19-0931 and DC B22-0901) defines autonomous vehicles and requires any self-driving vehicle operated in the district to have a human operator ready to take control. Conversion of conventional vehicles into self-driving cars is also limited to newer vehicles.

West Virginia

There are no self-driving car laws in West Virginia, and there have been no relevant executive orders. Self-driving vehicles are not specifically prohibited by law.

Wisconsin

The only law in Wisconsin pertaining to self-driving vehicles is SB 695, which defines autonomous vehicle platoons and exempts these vehicles from certain traffic rules about mandatory distances between vehicles on the road. In 2017, the governor signed an executive order to create a steering committee to provide advice on future regulations.

Wyoming

There are no self-driving car laws in Wyoming, and there have been no relevant executive orders. Self-driving vehicles are not specifically prohibited by law.