2021 Freightliner Cascadia problems, complaints & recalls

2021 Freightliner Cascadia recalls (21)

• Recall 26V583000Sep 9, 20262,404 vehicles
  ELECTRONIC STABILITY CONTROL (ESC) · SERVICE BRAKES, AIR:ANTILOCK

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2020-2023 Freightliner Cascadia and 2022 Western Star 49X vehicles previously repaired incorrectly under recall numbers 23V073 or 22V817. The brake modulator valves on the front axle may corrode and cause the vehicle to pull to one side during braking initiated by Electronic Stability Control (ESC) or Roll Stability Control (RSC).

  Risk: Brakes that pull to one side may cause a sudden change in vehicle direction, increasing the risk of a crash.

  Remedy: Dealers will replace the brake modulator valves, free of charge. Owner notification letters are expected to be mailed November 8, 2026. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is F1039. Vehicles repaired under the prior recalls will need the new repair completed.

• Recall 23V299000Apr 26, 2023266 vehicles
  ELECTRONIC STABILITY CONTROL (ESC)

  Daimler Trucks North America, LLC (DTNA) is recalling certain short wheelbase 2020-2024 Freightliner Cascadia, 2021-2024 Freightliner M2 Business Class, 2022 Western Star 4700, and 2020 Freightliner Classic Cascadia vehicles. The vehicle is equipped with an electronic stability control system and tire combination that may understeer during a J-turn. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 136, "Electronic Stability Control Systems on Heavy Vehicles."

  Risk: Understeering during a J-turn may increase the risk of a crash.

  Remedy: DTNA will replace the tires, free of charge. Owner notification letters were mailed June 19, 2023. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL971.

• Recall 23V208000Mar 28, 202324,282 vehicles
  EXTERIOR LIGHTING · EXTERIOR LIGHTING:HAZARD FLASHING WARNING LIGHTS

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2020-2021 Freightliner Cascadia and Western Star 49X vehicles. The hazard warning lights may flash improperly during an Advanced Braking Assist event. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 108, "Lamps, Reflective Devices, and Associated Equipment."

  Risk: Hazard warning lights that flash improperly may cause confusion for other drivers, increasing the risk of a crash.

  Remedy: Dealers will update the software controlling the hazard warning lights, free of charge. Owner notification letters were mailed May 18, 2023. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL851.

• Recall 23V073000Feb 10, 202370,167 vehicles
  ELECTRONIC STABILITY CONTROL (ESC) · SERVICE BRAKES, AIR:ANTILOCK:MODULATOR

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2017-2023 Freightliner Cascadia, 2020-2023 Western Star 49X, 2021-2023 Western Star 47X, and 2022 Freightliner 114SD vehicles. The brake modulator valves on the front axle may corrode and cause the vehicle to pull to the affected side during braking initiated by Electronic Stability Control (ESC) or Roll Stability Control (RSC).

  Risk: Brakes that pull to one side may cause a sudden change in vehicle direction, increasing the risk of a crash.

  Remedy: Dealers will inspect and replace the front brake modulator valves, as necessary. Some vehicles will have a software update which will alert driver when a replacement is required. All repairs will be performed free of charge. Owner notification letters were mailed beginning October 13, 2023. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL966.

• Recall 22V919000Dec 12, 202249 vehicles
  TIRES · WHEELS:RIM

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2020-2023 Freightliner 114SD, 2023 Freightliner 122SD, 2020 Western Star 4700, 2019-2022 Western Star 4900, 2019-2023 Freightliner Business Class M2, and 2021 Freightliner Cascadia vehicles. The vehicles are equipped with tires that are not compatible with their 8.25-inch rims. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard number 120, "Wheels and Rims-Other Than Passenger Cars."

  Risk: Driving with tires that are not compatible with their rims can reduce tire performance, increasing the risk of a crash.

  Remedy: Dealers will replace the tires, free of charge. Owner notification letters were mailed June 2, 2023. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-962.

• Recall 22V817000Nov 1, 2022219,390 vehicles
  FORWARD COLLISION AVOIDANCE: ADAPTIVE CRUISE CONTROL · SERVICE BRAKES, AIR:ANTILOCK:MODULATOR

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2017-2023 Freightliner Cascadia, 2020-2022 Freightliner Business Class M2, and 2022 Freightliner 114SD, and 2020-2023 Western Star 49X, 2021-2023 Western Star 47X, and 2021-2022 Western Star 57X vehicles. The brake modulator valves on the front axle may corrode and cause the vehicle to pull to the affected side during an Adaptive Cruise Control (ACC) braking event.

  Risk: Brakes that pull to one side during an ACC braking event may cause a sudden change in vehicle direction, increasing the risk of a crash.

  Remedy: Dealers will inspect and replace the front brake modulator valves, as necessary. Some vehicles will have a software update which will alert driver when a replacement is required. All repairs will be performed free of charge. Owner notification letters were mailed beginning October 16, 2023. DTNA's number for this recall is FL-958. This recall expands and replaces previous recall 20V-390. All vehicles previously repaired under recall 20V-390 will need to have the new remedy performed.

• Recall 20V567000Feb 16, 2022128,451 vehicles
  EXTERIOR LIGHTING:BRAKE LIGHTS

  Daimler Trucks North America LLC (DTNA) is recalling certain 2017-2021 Cascadia P4 vehicles. The brake lights may remain illuminated after the brake pedal has been released.

  Risk: If the brake lights remain illuminated, drivers may be unaware when the truck is actually slowing or stopping, increasing the risk of a crash.

  Remedy: DTNA will notify owners, and dealers will replace the 3-pin brake pressure switch with a 2-pin brake pressure switch along with a jumper harness, free of charge. DTNA issued owners an interim notification on November 17, 2020. Owner notification letters were mailed on November 21, 2021. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-863.

• Recall 21V965000Dec 13, 20212,843 vehicles
  FUEL SYSTEM, DIESEL:FUEL INJECTION SYSTEM:FUEL RAIL

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2020-2022 Western Star 4700, 2019-2022 Freightliner 114SD, 2021-2022 Western Star 49X, Freightliner Cascadia P4, 2022 Western Star 47X, 2021 Western Star WF110, 2020 Western Star WJ121, and 2019-2021 FCCC XCP Chassis vehicles. The fuel tubes between the fuel rail and the injectors for cylinders four, five, and six may fatigue and crack, which can result in a high pressure fuel leak.

  Risk: A high pressure fuel leak in the presence of an ignition source can increase the risk of a fire.

  Remedy: Dealers will replace the fuel tubes, and install vibration isolators, free of charge. Owner notification letters were mailed January 28, 2022. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-915.

• Recall 21V689000Sep 2, 2021113,085 vehicles
  STEERING:LINKAGES:DRAG:LINK:CONNECTION

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2019 Freightliner Classic Cascadia and 2019-2021 Freightliner Cascadia trucks. The drag link taper joint may not have been tightened sufficiently and could come loose, resulting in a complete separation of the drag link from the steering arm.

  Risk: Drag link separation can cause a complete loss of steering control, increasing the risk of a crash.

  Remedy: DTNA will inspect the drag link taper joint and repair it as necessary, free of charge. Owner notification letters were mailed on October 29, 2021. Owners may contact DTNA's customer service at 1-800-547-0712. DTNA's number for this recall is FL-900.

• Recall 21V481000Jun 25, 2021122,056 vehicles
  ELECTRICAL SYSTEM:12V/24V/48V BATTERY:CABLES

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2019-2022 Freightliner Cascadia P4, 2021 Western Star WH126, 2020 Western Star WJ121, and 2021-2022 Western Star 49X vehicles. The battery cable terminal may break, resulting in a loss of electrical power and unintended engine stall.

  Risk: An engine stall increases the risk of a crash.

  Remedy: Dealers will repair or replace the battery cables, free of charge. Owner notification letters were mailed on January 7, 2022. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-893.

• Recall 21V369000May 19, 20218,482 vehicles
  STEERING:LINKAGES:TIE ROD ASSEMBLY

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2021-2022 Freightliner 114SD, 122SD, Business Class M2, Cascadia, 108SD, Western Star 4900, 4700, 5700, Custom Chass RV Chassis, Custom Chass S2 Chassis, Custom Chass XC Chassis, Custom Chass XB Chassis, and Custom Chass MT Chassis. The tie rod clamps may be loose, which could result in loose tie rod ends that could break or detach.

  Risk: Detached or broken tie rod ends can result in steering loss, increasing the risk of a crash.

  Remedy: Dealers will replace the tie rod clamp bolts and nuts, free of charge. Owner notification letters were mailed December 23, 2021. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-888.

• Recall 21V357000May 14, 202172,510 vehicles
  EXTERIOR LIGHTING:HEADLIGHTS:BULBS

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2017-2022 Freightliner Cascadia vehicles equipped with halogen headlight assemblies. The halogen headlight bulb may dislodge during replacement and contact other vehicle components, possibly causing them to melt.

  Risk: Melting components can increase the risk of fire.

  Remedy: Dealers will install a foam grommet, cut a 4-inch access hole into the inner fender, and add a warning label on both fenders, free of charge. Owner notification letters were mailed on July 9, 2021. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-887.

• Recall 21V256000Apr 12, 202112,470 vehicles
  STEERING:CRITICAL FASTENERS · STEERING:LINKAGES:TIE ROD ASSEMBLY

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2021-2022 Freightliner Cascadia, Business Class M2, 114SD, 108SD, 122SD, Custom Chass S2 Chassis, Custom Chass XB Chassis, Custom Chass XC Chassis, and Custom Chass MT Chassis Western Star 4700, 4900, 5700 vehicles. The steering arm and tie rod bolts may have a defective seam that can fracture.

  Risk: A fractured bolt may cause a loss of steering, increasing the risk of a crash.

  Remedy: DTNA will notify owners, and dealers will replace the tie rod arm and steering arm bolts, free of charge. The recall began on June 10, 2021. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-884.

• Recall 21V209000Mar 24, 20212 vehicles
  POWER TRAIN:CLUTCH ASSEMBLY

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2021 Freightliner Cascadia and Western Star 4700 vehicles. The clutch flange may break.

  Risk: If flange failure occurs, loose parts may fall into the clutch pressure plate assembly, resulting in clutch disengagement, thereby increasing the risk of a crash.

  Remedy: DTNA will notify owners, and dealers will replace the clutch on the affected vehicles, free of charge. The recall began on May 7, 2021. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-881.

• Recall 21V073000Feb 12, 20217 vehicles
  ENGINE

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2021-2022 Freightliner Cascadia vehicles equipped with a Cummins X15 engine. The capscrews that attach the flywheel to the crankshaft may have been improperly torqued, allowing the flywheel to detach.

  Risk: A detached flywheel can cause loss of drive power, increasing the risk of a crash. Additionally, driveline pieces may be ejected from the engine compartment, increasing the risk of injury.

  Remedy: DTNA will work with the engine manufacturer Cummins Inc. to notify owners, and Cummins dealers will properly torque the capscrews and inspect for possible damage and, if necessary, repair any damage found, free of charge. The recall is expected to begin April 12, 2021. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-875.

• Recall 21V018000Jan 20, 2021133 vehicles
  SERVICE BRAKES, HYDRAULIC:FOUNDATION COMPONENTS:DISC:CALIPER

  Daimler Trucks North America, LLC (DTNA) is recalling 2021 Western Star 4700 and 5700, Freightliner Business Class M2, Cascadia, and Custom Chassis XC Chassis vehicles manufactured with a certain steering arm configuration with air disc brakes identified by the axle assembly supplier. On certain vehicles, one of the six brake caliper mounting bolts on the driver side steer axle may have been incorrectly tightened.

  Risk: The loose bolt could result in the other caliper bolts to loosen. Insufficiently tightened bolts may not provide adequate clamping force between the brake caliper and brake anchor plate, resulting in reduced brake effectiveness, increasing the risk of a crash.

  Remedy: DTNA will notify owners, and dealers will inspect and repair as necessary, free of charge. The recall began March 17, 2021. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-873.

• Recall 21V007000Jan 13, 20214,341 vehicles
  TIRES · TIRES:TREAD/BELT

  Daimler Trucks North America, LLC (DTNA) is recalling certain 2020-2022 Freightliner Cascadia sleeper trucks equipped with Bridgestone R284, R268, or R283S ECOPIA steer axle tires in conjunction with a specific air dam. The steer tires may experience tread separation or blow-outs while driving.

  Risk: Tread separation and/or blow-outs while driving may result in a loss of vehicle control, increasing the risk of a crash.

  Remedy: DTNA will notify owners, and dealers will replace the steer tires, free of charge. The recall began March 10, 2021. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL872.

• Recall 20V742000Nov 30, 20201,233 vehicles
  POWER TRAIN:CLUTCH ASSEMBLY

  Daimler Trucks North America LLC (DTNA) is recalling certain 2021 Freightliner Cascadia vehicles. The clutch flange may break due to the heat treating and stamping process.

  Risk: If flange failure occurs, loose parts may fall into the clutch pressure plate assembly, resulting in clutch disengagement, thereby increasing the risk of a crash.

  Remedy: DTNA will notify owners, and dealers will replace the clutch on the affected vehicles, free of charge. The recall began February 10, 2021. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-869.

• Recall 20V660000Oct 27, 20201,411 vehicles
  SUSPENSION:REAR:AXLE:SPINDLE

  Daimler Trucks North America LLC (DTNA) is recalling certain 2020-2021 Freightliner Cascadia, 2021 Freightliner 108SD, 114SD and Business Class M2 and Western Star 4700, 4900 and 5700 vehicles. The steer axle spindle nut snap-ring locking feature may be incorrectly installed or missing from the left spindle nut at the spindle.

  Risk: A missing or improperly installed locking snap ring can result in wheel-end failure and potentially a wheel-off/separation condition, increasing the risk of crash.

  Remedy: DTNA will notify owners, and dealers will inspect the hub cap plug, and reinstall or replace of the snap-ring as needed, free of charge. The recall began December 18, 2020. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-866.

• Recall 20V390000Jul 2, 2020164,326 vehicles
  SERVICE BRAKES, AIR:SUPPLY:QUICK RELEASE VALVE

  Daimler Trucks North America LLC (DTNA) is recalling certain 2017-2021 Freightliner Cascadia tractor trailers. The single brake modulator valve may be affected by chemical corrosion which can slow down the release timing and cause the brakes to pull to the affected side during automatic braking events.

  Risk: Brakes that pull to one side during automatic braking events may cause a sudden change in vehicle direction, increasing the risk of a crash.

  Remedy: DTNA will notify owners, and dealers will replace the front left and right single brake modulator valves will be replaced and spacers added, free of charge. The recall began August 28, 2020. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL-855.

• Recall 20V214000Apr 14, 202063,175 vehicles
  EXTERIOR LIGHTING

  Daimler Trucks North America LLC (DTNA) is recalling certain 2006-2020 Freightliner Columbia, 2006-2021 Freightliner Business Class M2, 2007-2020 Freightliner Coronado, 2014-2021 Freightliner 122 SD, 2007 Sterling A 9500, 2006 Freightliner Argosy, 2006-2007 Sterling AT9500, 2008-2021 Freightliner Cascadia, 2006-2008 Freightliner Classic, 2006-2011 Freightliner Century Class, 2006-2010 Freightliner FLD, and 2017 Western Star 5700 vehicles. The rear reflective tape may be partially covered by the mudflap hanger bracket, which may reduce the vehicle's visibility to other drivers on the road. As such, these vehicles fail to comply with the requirements of Federal Motor Vehicle Safety Standard (FMVSS) number 108, "Lamps, Reflective Devices, and Associated Equipment."

  Risk: The vehicle's rearward visibility may be reduced, increasing the risk of a crash.

  Remedy: DTNA will notify owners, and dealers will inspect and reposition the reflective tape to ensure that it is completely visible, as necessary, free of charge. The recall began May 29, 2020. Owners may contact DTNA customer service at 1-800-547-0712. DTNA's number for this recall is FL848.

NHTSA defect investigations

• EA25006Opened Oct 23, 2025Open

  Automatic Emergency Braking Errors

  On May 26, 2023, the Office of Defects Investigation (ODI) opened a Preliminary Evaluation (PE23010) to assess reports of false positive activation of the Automatic Emergency Braking (AEB) system in model year (MY) 2017-2022 Daimler Trucks North America (DTNA) vehicles. The reports alleged that activation of the AEB system occurred while driving with no apparent obstruction in the vehicle's forward path, resulting in sudden vehicle deceleration. DTNA indicated that it received of a total of 315 reports that may relate to the alleged defect in MY 2017-2022 DTNA vehicles. DTNA stated that the va…

• PE23010Opened May 26, 2023Closed Oct 23, 2025

  Automatic Emergency Braking Errors

  On May 26, 2023, the Office of Defects Investigation (ODI) opened a Preliminary Evaluation (PE23010) to assess reports of false positive activation of the Automatic Emergency Braking (AEB) system in model year (MY) 2017-2022 Daimler Trucks North America (DTNA) vehicles. The reports alleged that activation of the AEB system occurred while driving with no apparent obstruction in the vehicle's forward path, resulting in unexpected and sudden vehicle deceleration. ODI sent an information request letter to DTNA on June 15, 2023.In its September 1, 2023, response, DTNA indicated that it received of …

• PE21004Opened Feb 25, 2021Closed Jan 14, 2025

  Engine Electrical Wiring Harness Chafe

  The Office of Defects Investigation (ODI) opened this Preliminary Evaluation to investigate reports of engine electrical wiring harness chafe on the subject vehicles.ODI analysis found thousands of unique harness part numbers, spanning the two generations of vehicle chassis assembled at multiple vehicle assembly plants in two different countries, with multiple sub-models, incorporating over thirty powertrain choices.Each wiring harness could contain several dozen individual wires for power, ground and communication purposes depending on the multitude of equipment options available for custom v…

• RQ20001Opened Aug 31, 2020Closed Jun 26, 2025

  SAM Cab Water Intrusion

  On August 31, 2020, the Office of Defects Investigation (ODI) opened a recall query, RQ20001, to investigate the allegations of water intrusion into the truck cab signal-detect and activation module (SAM cab).The investigation further evaluated the effectiveness of the original recall remedy, and the installation of an updated drip shield as it relates to continual water intrusion resulting in the loss of electrical functions and potential fire.The potential hazard was the increased risk of a crash and injury in certain model year (MY) 2007-2021 Freightliner Cascadia P3 vehicles manufactured b…

Recent 2021 Freightliner Cascadia complaints

Excerpts of the newest owner complaints, lightly cleaned of personal details. Complaints are unverified owner reports.

1. Filed Sep 17, 2026OHBrakesDriver Assistance & Safety Tech

   Without warning an Automatic breaking event occurred and the tractor slammed on its breaks while on open road with no one near on a sunny day. I was bobtailing south.. That event caused my AEB system to disable itself and I also lost cruise control. The funny thing is even after the system is disabled I’m still having automatic breaking events around curves..

   NHTSA complaint #11765034 · source
2. Filed Sep 17, 2026742,227 miPAElectrical System

   Odometer Fraud. The contact purchased a 2021 Freightliner Cascadia. It was discovered that there was a mileage discrepancy. The vehicle was a dealer sale. At the time of purchase, the vehicle mileage was 438,861; however, service records listed the mileage at 742,227.

   NHTSA complaint #11764951 · source
3. Filed Feb 1, 2024NCCrash7 injuredTowedDriver Assistance & Safety Tech

   While vehicle approached a hazard blocking the roadway the forward collision and automatic braking feature did not engage; apparently due to the vehicle sensors not recognizing the hazard. The object in the roadway was a 53 ft van trailer that was laid on it's side with the translucent roof facing the approaching vehicle.

   NHTSA complaint #11569193 · source
4. Filed Dec 23, 2023OHBrakesElectrical SystemSteering

   When driving, there is a constant and very strong vibration throughout the entirety of the truck. This makes it difficult to steer and drive in a safe manner. I've replaced any parts that might be associated with this malfunction with brand new parts at the advice of professional mechanics (cost over $30,000) and it was to no avail. The truck is still malfunctioning and I have been left unable to work or barely working for 14 months. The vibration has caused many health…

   NHTSA complaint #11561665 · source
5. Filed Jul 4, 2023CABrakesEngineOther / Unknown

   My Emplyoer has not fixed anything on the truck, the truck shouldn’t be operating, doesn’t meet DOT Regulations, I was told not to go into any scales or weigh stations, loses air and the air doesn’t build back up properly, I lost all air in my breaks while driving on the road

   NHTSA complaint #11530297 · source
6. Filed Jun 29, 2023ILDriver Assistance & Safety Tech

   I'd like to report the automatic braking device on our company semi tractor. I work for a large mega carrier hauling all types of freight, with triples and doubles combination trailers. We operate with Freightliners, Kenworths, and Internationals. The tractor tractor I use is a 2021 Freightliner equipped with a safety feature, an automatic braking system to avoid collisions for stopped or slowed traffic ahead. The issue is, it randomly brakes with no obstructions ahead. I've…

   NHTSA complaint #11529649 · source
7. Filed May 31, 2023215,000 miNVDriver Assistance & Safety Tech

   The contact owns a 2021 Freightliner Cascadia. The contact stated while driving 65 MPH with the cruise control activated, the brakes applied independently. The contact took the vehicle to the local dealer, where it was diagnosed with needing the calibration of the radar. The vehicle was repaired but experienced the failure within a week. The contact took the vehicle back to the local dealer, where it was diagnosed with needing the radar to be replaced. The vehicle was…

   NHTSA complaint #11524581 · source
8. Filed Sep 19, 2022NVDriver Assistance & Safety TechSuspension

   This complaint is being filed in addition to my previous complaint which is complaint #1147128511471285. Both left and right vehicle airbag suspension height regulators were just replace a month ago, and once again, the right side airbag ride height regulator has blown apart, causing my semi truck to lean heavily to the right side, and wear out my right front steer tire exceedingly fast. And, the radar braking system erratically slams the brakes on at random times, which…

   NHTSA complaint #11485349 · source

Compare the 2021 Freightliner Cascadia with another vehicle →

Source: U.S. National Highway Traffic Safety Administration (NHTSA) Office of Defects Investigation public data, as of Oct 11, 2026. Complaints are submitted by owners and are not verified by NHTSA or by us; a complaint does not prove a defect exists. View this vehicle on NHTSA.gov Methodology