Efforts to Limit Maximum Truck Speeds

Two identical trucks can leave the same Louisville terminal with two very different top speeds. One carrier caps its fleet at 65 mph through the engine computer. The other never touches the setting. No law requires either choice, because the federal mandate that would have standardized truck speeds was withdrawn in 2025. Speed control sits in the carrier’s own policies, and after a high-speed truck crash, those policies and the data behind them often decide the case.

How Truck Speed Governors Work

A speed governor is built into the truck’s engine control module, the computer that manages fuel delivery and engine output. When the vehicle reaches the programmed maximum, the ECM cuts fuel to the engine so the truck cannot accelerate past that point. Most modern equipment needs no separate box. When FMCSA revived the speed limiter rulemaking in 2022, its advance notice covered commercial vehicles of 26,001 pounds or more that were already equipped with an electronic engine control unit capable of governing maximum speed. The hardware is already in the truck. The open questions are whether the carrier activated it and what number the carrier entered.

That setting is a record, and regulators treated it as one. The 2016 joint proposal from NHTSA and FMCSA would have required each new heavy truck to carry a readable speed setting, plus the two previous settings and the time and date each one was changed, all accessible through the vehicle’s on-board diagnostic connection. The agencies wrote it that way because a governor setting can be changed, and the history of those changes says a great deal about how a fleet operates.

A governor is different from the electronic logging device that tracks driving hours, and different from the ECM’s separate role as a recorder of speed, throttle, and brake inputs. The governor caps speed going forward. The ECM’s recorded data looks backward at what the truck was doing in the moments before a crash. A speed case uses both records: one shows what the carrier allowed, and the other shows what the driver did.

Speed and Truck Crash Severity

Higher truck speeds deliver more energy into smaller vehicles. According to the Insurance Institute for Highway Safety, 4,354 people died in large truck crashes in 2023, and 65 percent of them were occupants of cars and other passenger vehicles. Trucks often weigh 20 to 30 times as much as passenger cars, and a loaded tractor-trailer needs 20 to 40 percent more distance than a car to stop. Every additional mile per hour stretches that stopping distance further. IIHS also reports that deaths in large truck crashes were 38 percent higher in 2023 than in 2009, the lowest year since federal fatal crash data collection began in 1975.

The 2025 withdrawal notice acknowledges that the 2016 proposal rested on data suggesting that limiting heavy vehicle speeds would reduce the severity of the crashes those vehicles are involved in. The agencies said they could not pin down the effect on how many crashes happen, or on the costs.

Federal Speed Limiter Rulemaking

The federal effort to mandate truck speed governors ran for nearly two decades, produced two formal proposals, and ended without a rule. That history explains in litigation why governor use is voluntary and why a carrier’s own choices carry so much weight.

2016 Proposal

The rulemaking began with petitions from inside the industry: the American Trucking Associations and Schneider National, joined by nine other motor carriers, asked the agencies to require speed limiters, and the petitions were granted, as recounted in the Federal Register. On September 7, 2016, NHTSA and FMCSA jointly proposed requiring every heavy vehicle over 26,000 pounds to carry a speed limiting device maintained for the service life of the vehicle. The agencies asked for comment on settings from 60 to 68 mph and estimated that a 65 mph cap would save between 63 and 214 lives every year, with annual industry costs ranging from $209 million to $1.561 billion depending on the speed chosen and roughly $848 million in projected fuel and emissions savings.

The proposal drew 7,225 comments. Relatively few commenters answered the agencies’ question about which cap to pick, and those who did split nearly evenly across 60, 65, and 68 mph. The rule then stalled without final action.

2022 Revival

On May 4, 2022, FMCSA announced its intent to proceed through a carrier-based approach: motor carriers operating trucks of 26,001 pounds or more with ECUs capable of governing speed would have to set a maximum, at a number to be determined, and keep that setting for the service life of the vehicle. By the close of the comment period, docket FMCSA-2022-0004 had collected 15,638 comments from drivers, carriers, industry associations, and safety organizations.

2025 Withdrawal

On July 24, 2025, FMCSA and NHTSA withdrew both the 2016 proposal and the 2022 notice. The agencies wrote that the proposal lacked a sufficiently clear and compelling safety justification, raised federalism concerns about preempting state speed limits, and rested on analyses with significant data gaps about costs and benefits. The benefits calculation had counted lives saved, property damage avoided, and fuel savings, and the agencies concluded its limitations left too much uncertainty to support a final rule.

The withdrawal was classified as a deregulatory action under Executive Order 14192. As a result, no federal regulation requires a speed governor on any commercial truck, at any speed, and each carrier decides for itself whether to govern its fleet.

Fleet Speed Policies

With no mandate in place, speed governing lives in company policy, and the rulemaking record shows how split the industry is. Roughly 300 comments supported moving forward in 2022, including the National Transportation Safety Board, the National Safety Council, the Insurance Institute for Highway Safety, the Truckload Carriers Association, Road Safe America, and carriers such as C.R. England, according to the withdrawal notice’s summary of the docket. More than 15,000 comments opposed the rule, led by owner-operators and the Owner-Operator Independent Drivers Association, with companies such as United Parcel Service raising concerns of their own.

Many fleets adopted governors without a mandate. In the 2016 docket, Coach USA reported it had been running speed limiters set at 68 mph across its bus fleet for about a decade. Large carriers commonly govern their trucks for fuel economy and liability control, and some publicly supported a national standard so smaller competitors would have to do the same. When a carrier writes a governed speed into its own safety program and then lets a truck run ungoverned, the company has departed from the standard it set for itself.

Speed Differential Disputes

Opponents told FMCSA that capping trucks below the flow of traffic would force passenger cars into more passing maneuvers and create congestion, fatigue, and pay cuts for drivers. Supporters, including IIHS, answered that speed differentials between trucks and cars already exist and that lower truck speeds cut the kinetic energy a crash delivers. The withdrawal notice lays out both positions. The dispute ended the mandate, and each carrier still has a duty to manage the speed of its own fleet.

Governor Data as Evidence

Because the federal government withdrew the mandate, truck speed control now depends on what the carrier chose. That choice is documented in ECM settings, fleet management software, driver handbooks, and insurance underwriting files. After a serious truck crash involving speed, the truck accident team at Sam Aguiar Injury Lawyers looks at three scenarios.

Carrier Speed Policies Left Unenforced

Many carriers put a governed speed in writing: a safety manual, a driver agreement, or a representation to their insurer. When the ECM of the truck that caused the crash shows a higher cap than the policy states, or no cap at all, the gap between the two is evidence of negligence. Discovery puts the carrier’s written standard next to the truck’s configuration, and the company has to explain the difference. A safety rule a company writes and then ignores is often more damaging to its defense than having no rule at all.

Tampered or Disabled Governors

Governor settings can be raised, and governors can be switched off. The 2016 proposal would have made each truck store its current setting and its two previous settings with time and date stamps, precisely because regulators knew settings get changed. When a setting was raised or a governor disabled before a crash, the questions become who changed it, when, and what the carrier knew.

Carriers also have ongoing inspection duties. Federal rules under 49 CFR 396.11 require drivers to prepare a written inspection report at the end of each day’s work, and those driver vehicle inspection reports show whether the company was paying attention to its own equipment.

ECM Speed Data

Whether or not a governor was active, the ECM records the truck’s speed, throttle position, and brake use in the period surrounding a crash. That black box data can show a truck running at the top of an ungoverned engine’s range, or running governed and still too fast for traffic, weather, or road conditions. ECM data can be overwritten as a truck keeps driving, so preservation demands need to reach the carrier before the vehicle returns to service. Once preserved, the recorded speed becomes a fixed fact the insurance company cannot argue around.

When a carrier’s own program required governors and the company knowingly ran a truck without one, or left a disabled governor in service, that conduct can rise beyond ordinary negligence. Kentucky law allows punitive damages where the evidence shows conscious disregard for the safety of others, and governor tampering cases are among the clearest places that standard comes into play. Establishing it requires the carrier’s policy documents, fleet records, and ECM history side by side.

Speed Combined With Other Violations

Speed rarely acts alone in a serious truck case. Federal hours-of-service rules in 49 CFR 395.3 allow a property-carrying driver to drive up to 11 hours within a 14-hour window, and IIHS notes that driver fatigue is a known crash risk, with surveys indicating many drivers work longer than the rules permit. A fatigued driver at high speed has less attention and less stopping distance to work with at the same time. The firm’s page on hours of service violations covers how that side of a case is documented.

Equipment and road conditions compound speed the same way. A tire blowout that might be controllable at 55 mph can be catastrophic at 75. Rain, fog, and ice demand speeds below the posted limit, and weather-related truck accidents often come down to a driver who kept highway speed in conditions that called for far less. A complete investigation examines every contributing factor together and identifies each responsible party. The top causes of big truck accidents in Kentucky show where speed fits among the other factors.