Are Speed Limiters Mandatory in the United States?

No—speed limiters are not universally mandatory in the U.S. There is no federal requirement for passenger cars, and while federal regulators have proposed requiring speed limiters on certain heavy commercial vehicles, no final rule is in effect as of late 2024. Some fleets voluntarily use limiters or intelligent speed assistance (ISA), and a few local governments deploy them on municipal vehicles, but these are not nationwide mandates.

What Is a Speed Limiter?

A speed limiter (or governor) is a system that caps a vehicle’s maximum speed, typically through the engine control unit. Intelligent Speed Assistance (ISA) goes a step further by using GPS and/or camera data to detect posted limits and dynamically help drivers stay within them, either through warnings or active speed control.

Current U.S. Law and Policy

Passenger Cars and Light Vehicles

There is no federal requirement for factory-installed speed limiters or ISA on passenger cars and light-duty vehicles in the United States. Automakers may include optional “speed warning” or “speed limiter” features, but use is voluntary. This contrasts with the European Union, where ISA has been mandated on new models since 2022 and on all newly produced vehicles since 2024.

Commercial Trucks and Buses

Federal regulators have pursued speed limiters for heavy commercial motor vehicles (CMVs), but the policy remains in rulemaking. A 2016 proposal contemplated capping speeds on newly manufactured heavy vehicles; that effort stalled. The Federal Motor Carrier Safety Administration (FMCSA) reopened the issue in 2022 and has been developing a new proposal focused on CMVs equipped with electronic engine control units. As of October 2024, FMCSA has not issued a final rule, and no nationwide requirement is in force. The exact maximum speed and scope would be defined in a final rule, if adopted, and could take years to phase in.

State and Local Developments

No U.S. state currently mandates speed limiters for all vehicles. Some states impose lower posted speed limits on heavy trucks (for example, 55 mph in parts of California), but those are roadway speed limits—not device mandates. A few cities, notably New York City, have piloted ISA on municipal fleets and expanded its use, but these programs apply to city-owned vehicles and do not create requirements for the general public.

What Could Change Next?

FMCSA continues work on a speed limiter rule for heavy CMVs. Federal rulemakings typically involve a proposal, public comments, and a final rule, followed by compliance lead time. The final outcome—whether a mandate proceeds, which vehicles are covered, and what speed is selected—will depend on the rule text and the agency’s response to comments, safety data, and cost-benefit analyses. Stakeholders should watch FMCSA’s rulemaking docket and the Department of Transportation’s Unified Regulatory Agenda for updates.

How Prior Proposals Have Framed the Issue

Previous federal efforts provide a rough picture of how a future rule might be structured, though specifics are not final and could change. The points below summarize concepts that have appeared in past proposals or agency notices.

• Focus on heavy CMVs: Vehicles above a certain gross vehicle weight rating (historically around 26,000 pounds) have been the primary target for speed limiter requirements.
• Use of electronic engine controls: Mandates would rely on existing electronic engine control units to set and secure a maximum governed speed.
• Maximum speed under consideration: Prior proposals and industry positions have discussed caps in the 60–68 mph range, but no binding figure has been adopted.
• Tamper resistance and enforcement: Rulemaking has explored tamper-resistant settings and mechanisms to verify compliance during inspections.
• Phase-in periods: Agencies typically consider lead times to allow manufacturers and fleets to adapt.

These elements illustrate the regulatory direction but do not constitute current law. Only a published final rule would define actual requirements and timelines.

Why Many Fleets Use Speed Limiters Anyway

Even without a mandate, numerous carriers and corporate fleets cap vehicle speeds or use ISA for operational and safety reasons.

• Safety performance: Lower top speeds are associated with reduced crash severity and better stopping distances.
• Fuel and emissions savings: Aerodynamic drag rises with speed; capping speed can improve fuel economy and cut CO2.
• Cost control: Fleets report lower fuel spend, tire wear, and maintenance costs at moderated speeds.
• Insurance and risk: Some insurers and customers favor or require speed management policies.
• Driver support tools: ISA warnings can help drivers avoid inadvertent speeding in changing speed zones.

Voluntary adoption reflects a business case that often aligns safety with cost savings, even absent regulation.

Practical Takeaways for Drivers and Operators

If you’re deciding how to approach speed management now, consider the following steps while federal policy evolves.

• Stay informed: Monitor FMCSA announcements and the Federal Register for any proposed or final rules.
• Assess your fleet: Inventory which vehicles have configurable engine control units and current set speeds.
• Pilot technology: Test ISA or speed capping in small segments to evaluate impacts on safety and fuel.
• Policy and training: Pair any limiter settings with clear driver policies and coaching to maintain compliance and morale.
• Plan for flexibility: Be prepared to adjust governed speeds or documentation if a federal rule sets specific thresholds.

These steps can improve safety and cost efficiency today and reduce friction if future rules require formal compliance.

Summary

Speed limiters are not mandatory across the United States. There is no federal requirement for passenger cars, and while FMCSA is developing a rule that could require limiters on certain heavy commercial vehicles, no final nationwide mandate exists as of late 2024. Some fleets voluntarily cap speeds or deploy ISA for safety and cost reasons, and a few municipalities use ISA on their own vehicles. Stakeholders should track FMCSA’s rulemaking for potential changes and prepare operationally in the meantime.

Can speed limiters be turned off?

Exactly how you turn the limiter on and off varies from car to car. It may be a button on the steering wheel or an option in the same settings menu as other driver assistance features such as lane keeping assist. There may also be the option of turning the limiter permanently.

What is the speed limiter law in the US?

It’s official. The U.S. Department of Transportation has withdrawn a proposal to mandate speed limiters on commercial motor vehicles. The news is a little anticlimactic, as the DOT already announced its intentions to do so in late June.

Will speed limiters be mandatory?

Speed limiters have been a legal requirement for cars manufactured in Europe since 6 July 2022, and from 7 July 2024, all car manufacturers will be legally required to guarantee that all cars in their showrooms have speed limiters fitted. The limiters aren’t just an EU scheme, though.

Is it legal to remove a speed limiter in the US?

Legal and Safety Implications
Speed limiters are in place for a reason—they protect both drivers and pedestrians by enforcing safe driving limits. Legal Issues: Tampering with a speed limiter may violate local laws and regulations.