NHTSA Logo - This page is 508 compliant Frequently Asked Questions
on the Exemptions to the
Make Inoperative Prohibition

Since 1972, manufacturers, distributors, dealers and motor vehicle repair businesses have been prohibited from knowingly "making inoperative" any part of a device or element of design that has been installed on or in a motor vehicle in compliance with a Federal Motor Vehicle Safety Standard (FMVSS). Examples of such modifications include removing airbags, modifying door latches or reducing available crush space. On February 27, 2001, the National Highway Traffic Safety Administration (NHTSA) published a Final Rule that provides limited exemptions to this "make inoperative prohibition." These exemptions are available to businesses and individuals who modify vehicles to accommodate persons with disabilities either as drivers or as passengers.

This article was written to answer questions raised about the Final Rule by the National Mobility Equipment Dealers Association, a trade group representing modifiers of vehicles for people with disabilities. This article provides information on how to use the allowed exemptions and how to comply with the record keeping, labeling and consumer disclosure requirements of the regulation. A list of exemptions is at the end of the article. A question and answer format is used for easy access. Explanations of why specific exemptions were or were not included in the Final Rule are not included here. However, this information can be found in the preambles to the Notice of Proposed Rulemaking (NPRM) and the Final Rule. Those documents can be found at:

http://www.nhtsa.dot.gov/cars/rules/adaptive/Inoper/mkinop.fr.html, for the NPRM, and
http://dmses.dot.gov/docimages/pdf60/123015_web.pdf, for the Final Rule.

Some of the answers to the questions contain references to Letters of Interpretation (a.k.a. "interps") previously issued by the agency. These references contain the last name of the person to whom the letter was addressed, date the letter was issued, and a link for that letter on the NHTSA web site. You can find all of the Letters of Interpretation at http://www.nhtsa.dot.gov/cars/rules/interps/.

Terms used to describe types of businesses regulated by NHTSA:

Manufacturer means a person or business manufacturing or assembling motor vehicles or motor vehicle equipment or importing motor vehicles or motor vehicle equipment for resale.

Alterer means a person or business making changes to a certified vehicle. These changes do not include the addition, substitution, or removal of readily attachable components, such as mirrors or tire and rim assemblies. Nor do they include minor finishing operations such as painting. "Alterer" also means a person or business who alters a certified vehicle in such a manner that its stated weight ratings are no longer valid. All of these changes are made before the first purchase of the vehicle in good faith for purposes other than resale.

Repair business means a person or business holding itself out to the public to repair for compensation a motor vehicle or motor vehicle equipment. This term includes businesses that receive compensation for servicing vehicles without malfunctioning or broken parts or systems by adding or removing features or components to or from those vehicles or otherwise customizing those vehicles. Note that a "modifier", as the term is commonly used in the industry making vehicles accessible to persons with disabilities is considered a repair business by NHTSA.

Using the Exemptions

Registration with NHTSA is a prerequisite for using any exemption that affects the certification of a vehicle.

Who must register?

Any repair business or individual who modifies vehicles after the first retail sale to accommodate persons with disabilities must register to take advantage of any of the exemptions afforded under the rule.

The make inoperative prohibition (and so the exemptions) do not apply to individuals modifying their own vehicles, as long as they do not intend to make the changes for the purpose of resale. If you are making a modification to your own vehicle, Federal law does not apply, so you can do whatever you want (subject to any restrictions your state may impose). However, NHTSA urges individuals making such modifications to avoid unnecessary elimination of safety features.

How does the rule define the "first retail sale?"

A modifier cannot use the exemptions unless the vehicle has already been sold to the consumer. The "first retail sale" for purposes of this rule is the point at which the seller of the vehicle and the end user enter into a sales contract that identifies a specific vehicle to be delivered. This definition only applies to vehicle modifications made to accommodate a person with a disability.

How do I register?

Prepare a letter stating:

Send the letter to:

Administrator, National Highway Traffic Safety Administration,
400 Seventh Street, SW,
Washington, D.C. 20590.

NHTSA maintains a database of all registered modifiers. To hasten your entry into the database, you can also fax, FedEx, or UPS a copy of your letter to:

Maximo Aviles, NVS-22101
400 Seventh St, SW
Washington, DC 20590
Fax 202-366-3081

When do I have to register?

Businesses must register no later than 30 days after they modify a motor vehicle for use by a person with disabilities. Since the rule became effective April 30, 2001, businesses that have a history of modifying vehicles for persons with disabilities should already be registered, if they wish to take advantage of the exemptions. If they have not done so, they should register immediately. If changes to the information in the original letter occur (such as a change of address), a letter containing the new information must be submitted no later than 30 days after the changes occur.

Is there anything else I have to do to use the exemptions?

Yes, modifiers must prepare written documentation that:

This documentation can be as simple as notations on your invoice for the work performed. You must provide a copy to the customer. You must also retain a copy for five years. You do not send a copy to NHTSA, unless asked to do so by us.

In addition, the modifier must affix a permanent label next to the original or alterer's certification label that:

This documentation and labeling must be done for each vehicle modified.

How do I verify my registration and/or see other businesses who are registered?

All registered businesses and individuals are listed on the NHTSA web site. See http://www.nhtsa.dot.gov/cars/rules/adaptive/Modifier/Index.cfm, or call Maximo Aviles at 202-493-0227. The online database is updated about once a month.

Complying with the Exemptions

The following questions and answers address how the exemptions affect specific changes to vehicles.

Does the "make inoperative prohibition" apply to all changes to a vehicle?

No. It means that a modifier must not make any changes that make the vehicle noncompliant with an applicable FMVSS, or s/he must make those changes so that the vehicle would comply with the standard after modification. Many changes can be made that have no effect on a vehicle's compliance with the standards. Other changes, while they might affect compliance if done one way, can be made some other way so as to preserve compliance.

Can a modifier use the exemption for FMVSS 208 to disconnect air bags or install air bag on/off switches?

Yes, unless it is the only modification being made that would take the vehicle out of compliance; 49 CFR Part 595 Subpart B covers this situation. The new exemption to FMVSS 208 applies only where a retrofit air bag on-off switch cannot accommodate the individual's disability and the air bag system is affected in the course of a necessary modification. An example is deleting the air bag because a client needs a reduced-diameter steering wheel. The seating position must be supplied with a lap and shoulder safety belt meeting the requirements of FMVSS Nos. 209 and 210.

If the only thing you need to do to accommodate the vehicle user is to install an air bag on/off switch, follow 49 CFR Part 595 Subpart B. Use the make inoperative exemption for FMVSS 208 at 49 CFR 595.7(c)(14), if the client needs a switch or air bag deactivation in conjunction with other modifications for which you will be using exemptions under 49 CFR Part 595 Subpart C. If the only thing you plan to do that will take the vehicle out of compliance with any FMVSS is to deactivate the air bag, then the vehicle owner must write a letter to NHTSA's Chief Counsel requesting permission to do so, according to the instructions found on our web site at http://www.nhtsa.dot.gov/airbags/rule/section09.html.

Do the Part 595 Subpart C exemptions cover the new advanced air bag requirements of FMVSS No. 208?

Not as of the date of this article. NHTSA is reviewing a petition for rulemaking that requests the agency to add these new systems to the make inoperative exemptions.

If I cut the knee bolster just a little, must I use the FMVSS No. 208 exemption? At what point is the knee bolster compromised?

When it is necessary to use the exemptions is up to the judgment of the modifier. Each vehicle model and each modification is unique, so NHTSA cannot make any blanket statements about what modifications will cause a vehicle to no longer comply with a safety standard. Therefore, if you do not use an exemption, then the vehicle must comply with the standard after modification, so when in doubt, use the exemption. Using the exemption includes labeling the vehicle, giving documentation to the client and saving a copy of that documentation, according to the regulation. In the case of mechanical hand controls, NHTSA has a research report available at http://www-nrd.nhtsa.dot.gov/pdf/nrd-11/handcontrol.pdf that can give you guidance on whether cutting the knee bolster would affect the injury criteria used in FMVSS No. 208.

Is it necessary to deactivate the air bag and use the 208 exemption when installing a rim-mounted steering control device?

Not typically. Among the commonly used rim-mounted steering control devices (SCDs), NHTSA has not found evidence to suggest that the functioning of the air bag is degraded. Nor is there evidence that rim-mounted SCDs come off during a deployment. So, it does not appear necessary to deactivate the air bag just because you install a steering control device. For additional information on this issue, there are two research reports available from NHTSA. Call Gayle Dalrymple at 202-366-5559.

Issues Pertaining to Load Carrying Capacity

It is very dangerous to drive any vehicle whose load carrying capacity has been exceeded. Too much weight in a vehicle can cause difficulty steering and braking. It can also compromise a vehicle's safety by causing the tires to wear more quickly and unevenly and suspension parts and axles to wear more quickly. In extreme cases, overloading may cause catastrophic failure of any of these components. Therefore, when a vehicle is proposed for modification, the modifier should determine:

To determine whether a vehicle exceeds its GVWR, NHTSA's rules specify that only 150 pounds must be allowed for each designated seating position regardless of the weight of the intended users. However, consideration of the items described in the bullets above will help you deliver a vehicle that is not likely to be routinely overloaded by the user.

This information should then be used to calculate whether the modification would cause the vehicle to exceed the manufacturers Gross Vehicle Weight Rating (GVWR) or Gross Axle Weight Rating (GAWR) when in normal use. If it would, the vehicle should not be modified. Note: The "make inoperative" regulation requires modifiers to notify consumers of a vehicle's new load carrying capacity, if the load carrying capacity has been reduced by 220 pounds or more.

What is the intended meaning of load carrying capacity?

The term load carrying capacity was not defined in the make inoperative final rule but the intended meaning is the same as "vehicle capacity weight" as defined in FMVSS No. 110, Tire Selection and Rims. In brief, load carrying capacity is the Gross Vehicle Weight Rating (GVWR) minus the unloaded weight of the vehicle. (Lore, 4/25/02, http://www.nhtsa.dot.gov/cars/rules/interps/files/23668.rbm.html)

However, FMVSS No. 110 applies only to passenger cars and, under that standard, manufacturers are required to provide a car's load carrying capacity on a label. Therefore, when modifying a passenger car, the modifier has the load carrying capacity available. For vans, SUVs and pickups, many of the vehicle manufacturers provide the same sort of label, even though it is not required. If the load carrying capacity is not provided for these vehicles, the modifier must calculate the load carrying capacity as previously described.

What is the Gross Vehicle Weight Rating?

A Gross Vehicle Weight Rating is assigned to the vehicle by the manufacturer and "shall not be less than the sum of the unloaded vehicle weight, rated cargo load, and 150 pounds times the vehicle's designated seating capacity." (49 CFR 567.4(g)(3)).

"Unloaded vehicle weight" is defined as "the weight of a vehicle with maximum capacity of all fluids necessary for operation of the vehicle, but without cargo, occupants, or accessories that are ordinarily removed from the vehicle when they are not in use (49 CFR 571.3).

What is the Gross Axle Weight Rating?

The Gross Axle Weight Rating (GAWR) is the maximum weight that the designated axle system is designed to carry. It is set by the OEM and noted on the vehicle's original certification label. Alterers must determine whether their modifications affect the manufacturer's stated GVWR or GAWR. If they do, the alterer must specify the new GVWR or GAWR on the alterer's certification label (see 49 CFR 567.7). Note: A modifier or dealer should never accept an altered vehicle that does not have an alterer's certification label.

What is a rated cargo load?

The term rated cargo load is not defined by regulation, but generally it is the GVWR of the vehicle minus the combined weight of the occupied designated seating positions (150 pounds times the total number of designated seating positions) and the unloaded vehicle weight. (Lore, 4/25/02, http://www.nhtsa.dot.gov/cars/rules/interps/files/23668.rbm.html)

Does the "make inoperative rule" specifically require a modifier to weigh each vehicle before and after modification?

No. Any good faith method may be used to determine the reduction in load carrying capacity. In some cases, simply subtracting the weight of items removed from the vehicle and adding the weight of items added to the vehicle will work. However, the agency assumes the modifier will weigh the vehicle if this is the only way to determine whether the load carrying capacity has been significantly reduced by his or her modification. (Lore, 4/25/02, http://www.nhtsa.dot.gov/cars/rules/interps/files/23668.rbm.html)

If more than one modifier works on a vehicle, who is responsible for notifying the consumer if the cargo capacity is reduced by more than 220 pounds and who must put the modifier's label on the vehicle?

Each modifier must put a label on the vehicle and supply the consumer with the documentation required by 49 CFR 595.7(b) regarding his or her own work. The last modifier to work on the vehicle must inform the consumer if the original load carry capacity of the vehicle is reduced by more than 220 pounds, "after the modifications are completed" (49 CFR 595.7 (e)(5).)

How accurate must I be in documenting any reduction in load carrying capacity?

When documenting a reduction in load carrying capacity, accuracy must be within one percent of scale reading.

If I weigh vehicles to determine reduction in load carrying capacity does the scale have to be certified and legal for trade?

No, but it must have a current calibration traceable to the National Institute of Standards and Technology (NIST, formerly the National Bureau of Standards). See http://www.nist.gov/.

What effect does the placement of a wheelchair tie down intended for use by an occupied wheelchair have on a vehicle's load carrying capacity?

If an original designated seating position is replaced by a wheelchair tie down intended for use by an occupied wheelchair, 150 pounds must be allocated for that seating position. If the seat is permanently removed, its weight may be credited to the post-modification load carrying capacity. (Lore, 4/25/02, http://www.nhtsa.dot.gov/cars/rules/interps/files/23668.rbm.html and Conaway, 4/25/02, http://www.nhtsa.dot.gov/cars/rules/interps/files/23087.rbm.html)

What liability do dealers (automobile dealers in general as well as mobility dealers or modifiers) have if they sell a vehicle that is overweight?

We are speaking here only about the first retail sale of the vehicle. NHTSA's regulation requires manufacturers (49 CFR 567.4(g)(3)) and alters (49 CFR 567.7(b)) to label vehicles with the appropriate GVWR. They must also certify that the vehicle meets all applicable FMVSS at the time of alteration. If a vehicle is above GVWR it may well not be in compliance with several FMVSS, such as braking and tire standards. Once the vehicle is no longer in compliance, a dealer may not sell it under 49 U.S. C. Chapter 301 (formerly the Motor Vehicle Safety Act) and NHTSA can seek enforcement action. In addition, a dealer who knowingly sells an unsafe vehicle, whether new or used, may be liable under civil tort laws in the event of a problem with that vehicle. S/he may also be guilty of fraud. State laws address these issues.

Designated Seating Positions

How do designated seating positions affect a vehicle's load carrying capacity?

A designated seating position is defined as "any plan view location capable of accommodating a person at least as large as a 5th percentile adult female, if the overall seat configuration and design and vehicle design is such that the position is likely to be used as a seating position while the vehicle is in motion..." (49 CFR 571.3).

When seating positions are modified, the load carrying capacity of the vehicle may change. For example, if a designated seating position is modified to accommodate a removable seat with a wheelchair securement station, used when the seat is removed, the weight of the new seat and 150 pounds for its occupant must be included in the computation of the vehicle's load carrying capacity. The weight of the old seat is credited as an increase in load carrying capacity.

Does a wheelchair retention device qualify as a designated seating position?

The installation of a wheelchair retention device to restrain an unoccupied wheelchair as cargo is not a designated seating position. Therefore, the modifier is not required to allocate 150 pounds for that position. Once again, the customer must be informed if the weight of his or her wheelchair is included in the load carrying capacity (if the load carrying capacity has been reduced by 220 pounds). A wheelchair securement device intended for an occupied wheelchair is a designated seating position, for the purpose of determining load carrying capacity. You must allot 150 pounds for the occupant.

Should the Veterans Administration and State Vocational Rehabilitation agencies require that a modifier meet the requirements of the make inoperative rule before they assign work to the modifier?

Whether a modifier chooses to use the exemptions depends on the type of modifications and how they will be made. Only those modifiers who use the exemptions are required to register with NHTSA, label vehicles, and give documentation to clients (all requirements of the Part 595 rule). Therefore, there may be modifiers doing legitimate work who are not registered to use the exemptions. This would be either because their work is such that certification is not affected (for example, installing a left foot accelerator) or because they are doing the work in a manner that preserves certification.

What should someone, whether a vehicle modifier, vocational rehabilitation agency employee, or driver evaluator, do if s/he believes a modifier is doing work that does not comply with NHTSA's regulations?

Call NHTSA's Office of Vehicle Compliance. At the time this article was written the compliance engineer for the make inoperative regulation is Maximo Aviles, 202-493-0227, FAX 202-366-3081, eduardo.aviles@nhtsa.dot.gov.

List of portions of FMVSS for which make inoperative exemptions are available when vehicles are modified to accommodate persons with disabilities:

Exemptions are given for only 13 of our 56 motor vehicle standards, and then only under certain circumstances. For most of those 13 standards, the exemption is given only for particular portions of the standard. Those portions of the standards and the circumstances under which they may be made inoperative are listed below, where the number following the 'S' tells you the paragraph of that standard for which the exemption is allowed. The complete text of all FMVSS can be found in the Code of Federal Regulations in the volume containing Title 49, parts 400 to 999 (available from the Government Printing Office) or online at http://www.access.gpo.gov/nara/cfr/cfr-retrieve.html#page1 (Fill in the boxes on that web page like this: Title = 49, Part = 571, Section= the standard number you want to retrieve.)

FMVSS No. 101, Controls and displays
All of the standard, except for S5.2 (a), S5.3.1, S5.3.2, and S5.3.5.

FMVSS No. 108, Lamps, reflective devices, and associated equipment
Only S5.1.1.5, only in the case of a motor vehicle that is modified to be driven without a steering wheel or for which it is not feasible to retain the turn signal canceling device installed by the vehicle manufacturer.

FMVSS 114, Theft protection
Only S4.4 and S4.5, only for cases in which the original key-locking system must be modified.

FMVSS 118, Power-operated window, partition, and roof panel systems
Only S4(a), only for cases in which the medical condition of the person for whom the vehicle is modified necessitates the installation of a remote ignition switch to start the vehicle.

FMVSS 123, Motorcycle controls
Only S5.1 and S5.2.1, only for cases in which the modification necessitates the relocation of original equipment manufacturer=s controls.

FMVSS 135, Passenger car brake systems
Only S5.3.1, only for cases in which the modification necessitates the removal of the original equipment manufacturer foot pedal.

FMVSS 201, Occupant protection in interior impact
Only with respect to:

  1. targets located on the right side rail, the right B-pillar and the first right side "other" pillar adjacent to the stowed platform of a lift or ramp that stows vertically, inside the vehicle.
  2. targets located on the left side rail, the left B-pillar and the first left side "other" pillar adjacent to the stowed platform of a lift or ramp that stows vertically, inside the vehicle.
  3. targets located on the rear header and the rearmost pillars adjacent to the stowed platform of a lift or ramp that stows vertically, inside the vehicle.

FMVSS 202, Head restraints
S3(b)(1) and (b)(2) in any case in which the driver's head restraint must be modified to accommodate a driver with a disability, or
The entire standard in any case in which:

  1. a motor vehicle is modified to be operated by a driver seated in a wheelchair and no other seat is supplied with the vehicle for the driver;
  2. a motor vehicle is modified to transport a right front passenger seated in a wheelchair and no other right front passenger seat is supplied with the vehicle.

FMVSS 203, Impact protection for the driver from the steering control system
S5.1 in any case in which the modification necessitates a structural change to, or removal of, the original equipment manufacturer steering shaft, and
S5.2 in any case in which an item of adaptive equipment must be mounted on the steering wheel.

FMVSS 204, Steering control rearward displacement
The entire standard, in any case in which the modification necessitates a structural change to, or removal of, the original equipment manufacturer steering shaft.

FMVSS 207, Seating systems
Only S4.1, only in a case in which a vehicle is modified to be driven by a person seated in a wheelchair and no other driver's seat is supplied with the vehicle, provided that a wheelchair securement device is installed at the driver's position.

FMVSS 208, Occupant crash protection
S4.1.5.1(a)(1), S4.1.5.1(a)(3), S4.2.6.2, S5, S7.1, S7.2 and S7.4, only for the designated seating position modified, provided Type 2 or 2A seat belts meeting the requirements of 571.209 and 571.210 of this chapter are installed at that position.

FMVSS 214, Side impact protection
Only S5, only for the designated seating position modified, and only in cases in which the restraint system and/or seat at that position must be changed to accommodate a person with a disability.