Where U.S. “Speed Limiter” Rules Stand Today

The United States has no nationwide law that requires speed limiters on passenger cars, and there is no final federal rule yet mandating speed limiters on heavy trucks. Federal regulators have been pursuing a rule for certain commercial trucks, while some cities are piloting “intelligent speed assistance” on government fleets; however, as of late 2024, no broad, binding U.S. mandate is in effect. Below, we explain what’s proposed, what’s voluntary, and what may change in the near term.

Federal rulemaking: heavy trucks are the focus, but no final rule yet

For nearly a decade, federal agencies have debated requiring speed limiters on large commercial motor vehicles (CMVs). A 2016 proposal by the National Highway Traffic Safety Administration (NHTSA) and the Federal Motor Carrier Safety Administration (FMCSA) explored capping top speeds on heavy trucks. After periods of delay, FMCSA revived the effort in 2022 and has been preparing a formal proposal focused on using existing engine control modules (ECMs) to limit speed on CMVs above a certain weight threshold. As of late 2024, the rule is not final, and the agency’s own regulatory agenda targets a proposal in 2025.

Key elements that have been under consideration in federal discussions include:

• Which vehicles: CMVs with a gross vehicle weight rating (GVWR) of 26,001 pounds or more have been the main target population.
• How the cap would work: Using the vehicle’s ECM (already present on most modern heavy trucks) to set a maximum speed, with tamper-resistance requirements.
• Speed setting: Past dockets floated caps such as 60, 65, or 68 mph; FMCSA has not finalized a number and indicated it would be set during rulemaking.
• Regulatory split: Historically, NHTSA would require the equipment on new vehicles; FMCSA would require carriers to use the limiters in operation.
• Enforcement and compliance: Concepts included inspection procedures, fault/override reporting, and alignment with tire-speed ratings.

These points come from prior proposals and requests for comment; the specifics could change when FMCSA publishes an actual Notice of Proposed Rulemaking (NPRM). Congress has intermittently considered budget riders to block such a rule, but no permanent prohibition has become law. The bottom line: for now, there is no nationwide, enforceable speed-limiter requirement for heavy trucks.

Timeline and what to watch

Expect activity from FMCSA, not NHTSA, to drive the next step. In the U.S. Department of Transportation’s 2024 regulatory agenda, FMCSA targeted 2025 to issue a proposed rule on truck speed limiters. That process would still include public comment and could take additional time before any final rule would be adopted and phased in.

Passenger vehicles: no U.S. mandate; technology largely voluntary

There is no federal law requiring speed limiters or Intelligent Speed Assistance (ISA) on passenger cars sold in the U.S. Automakers may offer speed warnings or optional limiting features (for example, teen-driver settings), and insurers or fleet owners sometimes deploy telematics that nudge or cap speeds. By contrast, the European Union began requiring ISA on new cars (new model types from 2022, all new registrations from 2024). In the U.S., the National Transportation Safety Board (NTSB) has urged NHTSA to consider ISA requirements after high-speed fatal crashes, but NTSB recommendations are advisory, not binding.

Here’s how speed-related tech commonly appears in U.S. passenger vehicles today:

• Speed warning/alert systems: Use map and camera data to alert drivers when they exceed posted limits, but do not prevent speeding.
• Driver-selectable limiters: Some models allow the owner to set a maximum speed for teen or valet modes; these are voluntary and easily changed.
• Connected/insurance telematics: Devices or apps score driving behavior and may affect premiums; they can discourage speeding but typically do not hard-limit speed.
• Aftermarket governors: Specialty devices can cap speeds in fleet or parental-control contexts; legality depends on proper installation and compliance with safety standards.

None of these consumer-facing options amounts to a federal mandate, and drivers are not legally required to enable them. They reflect market offerings and policy interest, not a binding U.S. speed-limiter law.

State and local actions: pilots and fleets, not universal requirements

States have authority over speed limits and traffic enforcement, but, to date, no state has enacted a broad, enforceable requirement that all vehicles on its roads use speed limiters. Some local governments have moved ahead with fleet-specific rules and pilots to test ISA technology on government vehicles.

Notable examples include:

• New York City: The city has piloted ISA on municipal fleet vehicles and moved to expand its use within the city fleet as part of Vision Zero initiatives.
• Washington, D.C.: The District has explored ISA pilots within government fleets focused on speed compliance and safety outcomes.
• California (debate only as of late 2024): Lawmakers discussed a bill to require ISA on new cars on a future timeline, but it was not enacted statewide by late 2024.

These efforts are limited in scope—typically to city-owned or specific public vehicles—and do not create a general speed-limiter obligation for private motorists. They may, however, inform future policy.

What this means for drivers and fleets right now

Until federal rulemaking is finalized, obligations remain unchanged: comply with posted speed limits and existing safety regulations. Fleets may choose to install or maintain limiters for safety, liability, fuel economy, or insurance reasons, but that choice is generally voluntary outside specific contracts or employer policies.

If you operate or manage commercial vehicles, consider the following near-term realities:

• Policy tracking: Monitor FMCSA’s rulemaking docket for the forthcoming NPRM on truck speed limiters and submit comments if affected.
• Fleet practices: Many carriers already cap speeds (commonly in the mid-60 mph range) to reduce crashes and operating costs; this can ease future compliance.
• Contracts and insurance: Shippers and insurers may encourage or require speed policies, telematics, or limiters independent of federal mandates.
• State differences: Speed limits and enforcement vary by state, especially where car and truck speed limits differ; ensure routing and policies account for those differences.

Preparation now—through voluntary policies and technology—can reduce operational friction if a federal rule eventually takes effect for heavy trucks.

Frequently asked points

These are the most common clarifications about “speed limiter law” in the U.S. context.

• Is there a U.S. law that limits how fast all vehicles can go? No. Drivers must obey posted speed limits, but there is no universal hardware or software cap mandated for all vehicles.
• Are truck speed limiters currently required? No nationwide mandate is in force as of late 2024. FMCSA is working toward a proposal targeting heavy CMVs.
• What about passenger cars? No federal requirement. Some cities are installing ISA on their own fleets; some automakers offer optional controls.
• Could Congress block a truck limiter rule? Congress can use appropriations riders, but none has created a lasting prohibition; the outcome depends on future legislation.
• How soon could a truck rule arrive? FMCSA signaled a 2025 proposal. After public comments and revisions, any final rule would likely have a lead time before compliance kicks in.

The answers hinge on evolving federal rulemaking and legislative activity; stakeholders should watch FMCSA’s docket and congressional developments.

Summary

There is no nationwide U.S. “speed limiter law” today. FMCSA is preparing a proposed rule that could require speed limiters on heavy commercial trucks, but it was not finalized as of late 2024. Passenger vehicles face no federal mandate, though local pilots—particularly in city fleets—are expanding. For now, speed compliance remains a matter of obeying posted limits, with speed-limiting technology largely voluntary outside specific fleet policies.

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.

Are speed limiters mandatory in the US?

The Federal Motor Carrier Safety Administration (FMCSA) has officially withdrawn its proposed rule mandating speed limiters on commercial motor vehicles, effective July 24, 2025, as published in the Federal Register.

How much can you go over the speed limit in the USA?

Most states don’t explicitly allow speeding, regardless of the situation. However, some police officers exercise discretion, allowing drivers to exceed the speed limit by a few miles per hour when passing (under certain circumstances).