NHTSA Interpretation File Search
Overview
NHTSA's Chief Counsel interprets the statutes that the agency administers and the standards and regulations that it issues. Members of the public may submit requests for interpretation, and the Chief Counsel will respond with a letter of interpretation. These interpretation letters look at the particular facts presented in the question and explain the agency’s opinion on how the law applies given those facts. These letters of interpretation are guidance documents. They do not have the force and effect of law and are not meant to bind the public in any way. They are intended only to provide information to the public regarding existing requirements under the law or agency policies.
Understanding NHTSA’s Online Interpretation Files
NHTSA makes its letters of interpretation available to the public on this webpage.
An interpretation letter represents the opinion of the Chief Counsel based on the facts of individual cases at the time the letter was written. While these letters may be helpful in determining how the agency might answer a question that another person has if that question is similar to a previously considered question, do not assume that a prior interpretation will necessarily apply to your situation.
- Your facts may be sufficiently different from those presented in prior interpretations, such that the agency's answer to you might be different from the answer in the prior interpretation letter;
- Your situation may be completely new to the agency and not addressed in an existing interpretation letter;
- The agency's safety standards or regulations may have changed since the prior interpretation letter was written so that the agency's prior interpretation no longer applies; or
- Some combination of the above, or other, factors.
Searching NHTSA’s Online Interpretation Files
Before beginning a search, it’s important to understand how this online search works. Below we provide some examples of searches you can run. In some cases, the search results may include words similar to what you searched because it utilizes a fuzzy search algorithm.
Single word search
Example: car
Result: Any document containing that word.
Multiple word search
Example: car seat requirements
Result: Any document containing any of these words.
Connector word search
Example: car AND seat AND requirements
Result: Any document containing all of these words.
Note: Search operators such as AND or OR must be in all capital letters.
Phrase in double quotes
Example: "headlamp function"
Result: Any document with that phrase.
Conjunctive search
Example: functionally AND minima
Result: Any document with both of those words.
Wildcard
Example: headl*
Result: Any document with a word beginning with those letters (e.g., headlamp, headlight, headlamps).
Example: no*compl*
Result: Any document beginning with the letters “no” followed by the letters “compl” (e.g., noncompliance, non-complying).
Not
Example: headlamp NOT crash
Result: Any document containing the word “headlamp” and not the word “crash.”
Complex searches
You can combine search operators to write more targeted searches.
Note: The database does not currently support phrase searches with wildcards (e.g., “make* inoperative”).
Example: Headl* AND (supplement* OR auxiliary OR impair*)
Result: Any document containing words that are variants of “headlamp” (headlamp, headlights, etc.) and also containing a variant of “supplement” (supplement, supplemental, etc.) or “impair” (impair, impairment, etc.) or the word “auxiliary.”
Search Tool
NHTSA's Interpretation Files Search
| Interpretations | Date |
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ID: aiam2280OpenMs. Constance Newman, Assistant Secretary for Consumer Affairs and Regulatory Functions, Department of Housing and Urban Development, 451 Seventh Street, S.W., Washington, D.C. 20410; Ms. Constance Newman Assistant Secretary for Consumer Affairs and Regulatory Functions Department of Housing and Urban Development 451 Seventh Street S.W. Washington D.C. 20410; Dear Ms. Newman: I am writing in response to questions that have been raised about th National Highway Traffic Safety Administration's (NHTSA) authority to regulate mobile homes. As you may know, mobil homes have been considered to be 'motor vehicles' as that term is defined in the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S.C. 1391 et seq.) ('the Vehicle Safety Act'). As such, they have been subject to Federal Motor Vehicle Safety Standard No. 108 (*Lamps, Reflective Devices, and Associated Equipment) and to our authority regarding the notification and remedy of noncompliances and defects related to motor vehicle safety.; The National Mobile Home Construction and Safety Standard Act of 197 (42 U.S.C. 5401 et seq.) ('the Mobile Home Act') established within the Department of Housing and Urban Development a comprehensive program for the regulation of mobil homes. We have concluded that one result of that statute's enactment was the implied repeal of the NHTSA's authority with respect to mobile homes. Accordingly, we consider that the enactment had the effect of amending the Vehicles Safety Act's definition of 'motor vehicle' to exclude 'mobile homes' as the latter term is defined in the Mobile Home Act. We are preparing a Federal Register notice that will reflect this conclusion.; Sincerely, James B. Gregory, Administrator |
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ID: aiam5545OpenMr. Stephen M. Padula Industry Standards and Government Regulations Uniroyal Goodrich Tire Company P.O. Box 2501 Greenville, SC 29602; Mr. Stephen M. Padula Industry Standards and Government Regulations Uniroyal Goodrich Tire Company P.O. Box 2501 Greenville SC 29602; "Dear Mr. Padula: This responds to your letter of March 21, 1995, i which you asked whether it is permissible to have a treadwear grade of 00 or 000 on tires under the Uniform Tire Quality Grading Standards (UTQGS), 49 CFR 575.104. The answer to your question is yes. As you know, the UTQGS currently provide that all new passenger car tires sold in the United States must be graded by their manufacturers or brand name owners for treadwear, traction, and temperature resistance. The grades must be assessed in accordance with paragraphs (d)(1)(i)(A) and (B) of the UTQGS and must be molded into or onto the tire sidewall. Paragraph (d)(2)(i) requires the treadwear grade to be expressed as 2 or 3 digits, representing the percentage (P) of the NHTSA nominal treadwear value, computed as follows: Projected P = mileage x 100 30,000 The percentage derived from the above formula is then rounded off to the nearest lower 20-point increment to arrive at the treadwear grade. In your letter you proposed a hypothetical example of a tire with a projected mileage of 5,000 miles, which would compute as follows: P = 5,000 x 100 = 16.67 30,000 Rounded off to the nearest lower 20-point increment, the treadwear rating for that tire would be 00 or 000. Your example would be correct, if tires still exist that have a projected tread life of 5,000 miles. Although NHTSA has not found any tires so rated, under the current provisions of the UTQGS, it is possible, as demonstrated by your example, to have a UTQGS treadwear rating of 00 or 000. I hope this information is helpful to you. Should you have any questions or need additional information, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0317OpenMr. Keitaro Nakajima, General Manager, Toyota Motor Company, Ltd., Lyndhurst Office Park, 1099 Wall Street West, Lyndhurst, New Jersey 07071; Mr. Keitaro Nakajima General Manager Toyota Motor Company Ltd. Lyndhurst Office Park 1099 Wall Street West Lyndhurst New Jersey 07071; Dear Mr. Nakajima: #This is to confirm your understanding that the DO symbol, which represents the tire manufacturer's certification that the tire complies with the passenger car tire standard, is required on tires installed on multipurpose passenger vehicles, if such tires are originally designed and have passenger car tire size designations. However, since Standard No. 110 does not, at the present time, apply to multipurpose passenger vehicles,the responsibility for assuring that these tires contain the DOT symbol is limited to the tire manufacturer. #Sincerely, Lawrence R. Schneider, Acting Chief Counsel; |
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ID: aiam5115OpenThe Honorable Paul David Wellstone United States Senate 2550 University Avenue, West Court International Building St. Paul, MN 55114-1025; The Honorable Paul David Wellstone United States Senate 2550 University Avenue West Court International Building St. Paul MN 55114-1025; Dear Senator Wellstone: Thank you for your letter on behalf of you constituents, Ms. Tutti Sherlock and Ms. Mary Bock, regarding the application of the National Highway Traffic Safety Administration's (NHTSA's) school bus standards to Head Start facilities. Your constituents ask that NHTSA inform the Minnesota Department of Transportation that we do not require school bus manufacturers to provide school bus equipment, such as stop arms and special stop lights, on Head Start buses. They base this request on their belief that in 1985, NHTSA said that states may decide which regulations should apply to Head Start buses. They also believe that stop arms and lights for Head Start buses are unnecessary, and that painting Head Start buses yellow could be confusing. We cannot provide the requested interpretation, because the understanding of your constituents is incorrect. By way of background, your constituents' concerns relate to two sets of regulations, issued under different Acts of Congress. The first of these, the Federal motor vehicle safety standards (FMVSS's) issued under the National Traffic and Motor Vehicle Safety Act ('Safety Act'), apply to the manufacture and sale of new motor vehicles. NHTSA has issued a number of FMVSS's for school buses, including FMVSS's requiring these buses to have a stop arm and warning lights. The Safety Act requires that each person selling a new bus (defined in our regulations as a vehicle designed for 11 or more persons) to a primary, preprimary or secondary school must sell a bus that is certified to the FMVSS's for school buses. State law cannot change this requirement. The question of whether Head Start facilities are 'schools' under the Safety Act has been addressed by NHTSA since the beginning of the school bus FMVSS's. The agency's longstanding position is that Head Start programs are primarily educational in focus rather than custodial, and are therefore 'schools' under the Safety Act. We base this conclusion on a review of the goals and functions of the Head Start program (see, e.g., 45 CFR 1304.1-3), and on past NHTSA interpretations of 'school.' NHTSA has stated its position that Head Start facilities are schools most recently in an August 21, 1992 letter to Mr. Chuck Anderson of the Minnesota Department of Transportation. Any new bus that is sold to a Head Start facility must have the safety features of a school bus at the time of the vehicle's sale, including the stop arm and signal lights. However, the Safety Act does not require Head Start facilities to use school buses or any other particular vehicle, nor does it require school buses to be painted yellow. The maintenance and operational characteristics of school buses are matters left to the individual states. NHTSA's second set of school bus regulations, issued under the Highway Safety Act, is a set of recommendations to the states for developing effective pupil transportation programs. Highway Safety Program Guideline No. 17, 'Pupil Transportation Safety' (copy enclosed), recommends that any vehicle designed for 11 or more persons that is used as a school bus should comply with the FMVSS's for school buses and should be painted yellow. However, Guideline 17 would affect the operation of your constituents' school buses only to the extent that Minnesota has incorporated it into state law. I hope this information will be helpful in responding to your constituents. Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam0792OpenMr. J. Mulvey, Bakelite Xylonite Limited, Industrial Products Division, Brantham, Manningtree, Essex COll lNJ (sic), England; Mr. J. Mulvey Bakelite Xylonite Limited Industrial Products Division Brantham Manningtree Essex COll lNJ (sic) England; Dear Mr. Mulvey: Thank you for your letter of June 28, 1972, inquiring about th applicability of Federal Motor Vehicle Safety Standard No. 302 to safety glazing.; Safety glazing is not included in the list of motor vehicle interio materials to which Standard No. 302 applies. However, if your plastic material is used as all or part of a component of vehicle occupant compartments included under S4.1 of the standard, then, it is required to meet the requirements of Standard No. 302. A copy of this standard is enclosed for your reference.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam0268OpenCharles O. Verrill, Jr., Esq., Messrs. Patton, Blow, Verrill, Brand & Boggs, 1200 17th Street, N.W., Washington, DC 20036; Charles O. Verrill Jr. Esq. Messrs. Patton Blow Verrill Brand & Boggs 1200 17th Street N.W. Washington DC 20036; Dear Mr. Verrill: In your letter of November 16 you inquire whether the Bureau' interpretation of 'overall width' (49 CFR S 571.21, with reference to Federal Motor Vehicle Safety Standard No. 108) can 'embrace the situation where the entire lighting assembly, including the taillamps, stop lamps, and back-up lamps, as well as signal lamps, add to the dimension of the vehicle'.; Since 'overall width' means 'the nominal design dimension of the wides part of the vehicle exclusive of signal lamps [and] marker lamps . . . .', the Bureau concurs in your requested interpretation. Taillamps, stop lamps, and back-up lamps are 'signal' lamps, and their combined mounting in a fixture which may extend beyond the widest part of a boat trailer does not result in a corresponding increase in the 'overall width' of the trailer.; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam5590OpenMr. Jim Burgess Engineering Manager Independent Mobility Systems, Inc. 4100 West Piedras St. Farmington, NM 87401; Mr. Jim Burgess Engineering Manager Independent Mobility Systems Inc. 4100 West Piedras St. Farmington NM 87401; Dear Mr. Burgess: This responds to your letter of May 18, 1995 to thi office and your telephone conversations with Walter Myers of my staff on June 14 and 27, 1995, concerning an exclusion in Federal Motor Vehicle Safety Standard (FMVSS) No. 206, Door locks and door retention components. The standard excludes from its requirements doors equipped with wheelchair lifts and either a visual or audible alarm system. You state that your company converts minivans into wheelchair accessible vehicles by lowering the floor and adding a wheelchair ramp to the right rear side sliding door area, with an audible and/or visual alarm. The issue you raise is whether FMVSS No. 206's exclusion of wheelchair-equipped doors also excludes a ramp-equipped door. The answer is no. FMVSS No. 206 requires that side doors leading directly into a compartment containing one or more seating positions must conform to the standard. However, paragraph S4 of the standard states: S ide doors equipped with wheelchair lifts and which are linked to an alarm system consisting of either a flashing visual signal located in the driver's compartment or an alarm audible to the driver which is activated when the door is open, need not conform to this standard. FMVSS No. 206 was amended to add the wheelchair lift exception by final rule dated March 27, 1985 (50 FR 12029, copy enclosed). The agency's rationale was that when not in use, wheelchair lifts are stowed in a vertical position parallel to and in close proximity to the interior surface of the vehicle door, thus providing a barrier to occupant ejection if the door opened while the vehicle was in motion or in the event of a crash. The alarm requirement was intended to alert the driver to a door that was open on a vehicle that was in motion. While the information you provided us showed that your wheelchair ramp is also stowed in a vertical position parallel to and in close proximity to the door and that you install audible and/or visual alarms for the driver, wheelchair lifts and wheelchair ramps are distinctly different components. Although they serve the same purpose and are similarly configured when in the stowed position, this agency cannot by interpretation say that 'lift' includes 'ramp.' In order to amend the standard to exclude wheelchair ramps as well as lifts, rulemaking action would be required. You may petition this agency to do rulemaking, under 49 CFR Part 552 (copy enclosed). This agency will entertain your petition and decide whether a rulemaking proceeding is appropriate. I hope this information is helpful to you. Should you have any further questions or need any additional information, please feel free to contact Mr. Myers at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosures (2) 1985 final rule Part 552; |
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ID: aiam2255OpenMr. J.L. Chancey, President, Trail-O-Matic, Inc., P.O. Box 2367, Jacksonville, FL 32203; Mr. J.L. Chancey President Trail-O-Matic Inc. P.O. Box 2367 Jacksonville FL 32203; Dear Mr. Chancey: This responds to your March 8, 1976, request to know the status of 'lo trailers' under Standard No. 121, *Air Brake Systems*, whether the exclusion for 'heavy hauler' trailers terminates September 1, 1976, and what the penalties are for non-compliance with an applicable Federal motor vehicle safety standard. You indicate that you may know of some manufacturers that do not comply with Standard No. 121 and suggest that all persons concerned with the standard be advised of the status of the regulation.; Without description of the 'log trailers' in question, it is no possible to determine if Standard No. 121 applies to them. Most pole trailers and trailers equipped with any axle having a gross axle weight rating of 24,000 pounds or more are examples of vehicles that may be excluded from the standard. Mr. Herlihy of this office has already sent applicable documents to you under separate cover. The exclusion from the standard for 'heavy hauler' trailers was extended recently and now terminates September 1, 1977.; Section 108(a)(1) of the National Traffic and Motor Vehicle Safety Ac (15 U.S.C. S1397(a)(1)) prohibits the sale and false or misleading certification of a non-complying vehicle to which a standard is applicable. Each violation of these provisions makes the manufacturer liable to a maximum civil penalty of $1,000 for each violation, up to a total of $800,000 for a related series of violations. (15 U.S.C. S1398). You may advise our Office of Standards Enforcement of any violations of which you are aware.; The NHTSA finds it impracticable to notify directly every intereste person of each of its regulatory actions. Each action is made public and is widely distributed by commercial services and trade associations. Enclosed is an information sheet that explains the various means to obtain copies of our regulations.; Yours truly, Frank Berndt, Acting Chief Counsel |
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ID: aiam0507OpenMr. Albert D. Ekegren, Vice President and General Manager, Cats-Eye Lamp Division, Holophane Company, Inc., P.O. Box 567, Columbus, OH, 43216; Mr. Albert D. Ekegren Vice President and General Manager Cats-Eye Lamp Division Holophane Company Inc. P.O. Box 567 Columbus OH 43216; Dear Mr. Ekegren: This is in response to your letter of October 27, 1971, to David H Soule of the National Highway Traffic Safety Administration concerning the requirements of Motor Vehicle Safety Standard No. 108 for school bus lighting.; You are concerned with paragraph S4.1.4(b)(ii) which reads: >>>'The system shall be wired so that the amber signal lamps ar activated only by manual or foot operation, and if activated, are automatically deactivated and the red signal lamps automatically activated when the bus entrance door is opened.'<<<; You have commented that 'the use of the automatic system would make i mandatory that the red lights go on when the door is open and stop traffic where unnecessary--such as railroad crossings.' That is not correct. You will see from S4.1.4(b)(ii) that the red lamps are not automatically activated when the bus entrance door opens unless there has been prior manual or foot activation of the amber signal lamps.; You are also concerned with the fact 'that this automatic system i patented and only one manufacturer has the right to make it.' Since you have not enclosed the copy of the patent enclosed in attorney Smith's letter to you dated June 4, 1970, I am unable to comment on your statement. I would like to point out that Standard No. 108 does not mandate the use of an amber-red lamp system, a system of red lamps only is also permissible. If the amber-red lamp system is used, paragraph S4.1.4(b)(ii) does not specify system design but only that the system be wired so that the driver can activate the amber lamp system at his option, and if he does activate it, that it automatically be deactivated and the red system automatically activated when the bus entrance door is opened.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4817OpenMs. Carol C. Verenes District Transportation Supervisor Aiken County Public Schools 843 Edgefield Avenue, N.W. P.O. Box 1137 Aiken, South Carolina 29802-1137; Ms. Carol C. Verenes District Transportation Supervisor Aiken County Public Schools 843 Edgefield Avenue N.W. P.O. Box 1137 Aiken South Carolina 29802-1137; "Dear Ms. Verenes: This responds to your letter of September 7, 199 requesting 'written correspondence relative to the U.S. Department of Transportation, National Highway Traffic Safety Administration, adopted safety standards effective April 1, 1977, which applies to vans transporting school children.' Additionally, you requested 'information pertaining to Federal Motor Vehicle Safety Standards No. 220, 221, and 222' because your district is considering modifying vans to transport school children. By telephone conversation with Mary Versailles of my staff on September 28, 1990, you stated that your school district has stopped using its 12-15 passenger vans to transport school children, because you had been informed that such use violated federal law. You requested information on what needed to be done to modify your vans to comply with Federal school bus regulations. You also asked if a dealer who had sold your school district new vans which did not comply with school bus regulations would be required to modify the vans or replace them with complying vans. I am pleased to have this opportunity to clarify the operation of Federal law as it applies to school buses. Federal law regulates the manufacture and sale of new school buses. The National Highway Traffic Safety Administration (NHTSA) defines 'school bus' as a motor vehicle designed for carrying 11 or more persons, including a driver, and sold for transporting students to and from school or school-related events. Note that in determining whether a vehicle is a school bus, one must consider both the vehicle's seating capacity, and its intended use. Thus, under federal law, a 12-15 passenger van is considered a school bus if its intended use is to transport school children. NHTSA has issued Federal motor vehicle safety standards applicable to all new school buses. It is a violation of Federal law for any person to sell as a school bus any new vehicle that does not comply with all school bus safety standards. On the other hand, without violating any provision of Federal law, a school district may use a vehicle to transport school children, even if the vehicle does not comply with Federal school bus regulations. This is so because the individual States have authority over the use of vehicles. Therefore, to determine whether your school district may use noncomplying vans to transport school children, you must look to state law. In addition, using noncomplying vans as a school bus could result in increased liability in the event of an accident. You might want to consult your attorney and insurance company to discuss this matter. Your first question asked what must be done to bring your vans into compliance as a school bus. Again, I must emphasize that there is no regulation under Federal law requiring your school district to retrofit your vans to comply with federal regulations. However, the following is a list of all Federal motor vehicle safety standards that include requirements for school buses: Standards No. 101 through 104, Standard No. 105 (school buses with hydraulic service brake systems), Standards No. 106 through 108, Standards No. 111 through 113, Standard No. 115, Standard No. 116 (school buses with hydraulic service brake systems), Standards No. 119 and 120, Standard No. 121 (school buses with air brake systems), Standard No. 124, Standards No. 201 through 204 (school buses with GVWR of 10,000 pounds or less), Standard No. 205, Standards No. 207 through 210, Standard No. 212 (school buses with GVWR of 10,000 pounds or less), Standard No. 217, Standard No. 219 (school buses with GVWR of 10,000 pounds or less), Standard No. 220, Standard No. 221 (school buses with GVWR greater than 10,000 pounds), Standard No. 222, Standards No. 301 and 302. Some of the standards which have unique requirements for school bus vehicles include, but are not necessarily limited to, Standards No. 105, 108, 111, 217, and 301, other standards (220, 221, and 222) are applicable only to school bus vehicles. Modification of the vehicles to comply with Standards No. 220 and 222 will be difficult and require recertification. The Federal motor vehicle safety standards are contained in Title 49 of the Code of Federal Regulations (CFR), Part 571. You may find a copy of 49 CFR Part 571 at a Federal Depository Library in your State. If you so choose, you may purchase a copy of the volume of Title 49 which includes Part 571 from the United States Printing Office (GPO), Washington, D.C., 20402, (202) 783-3238. Your second question asked whether the sale between the dealership and the school could be dissolved if you determined that any purchases of new vans did not comply with the regulations for school buses. While we have no regulations which void or 'dissolve' sales of noncomplying motor vehicles, the school might be able to contact the dealership that sold the noncomplying school buses and arrange to have the vehicles repurchased. In addition, if you believe that you had been sold noncomplying vehicles, and that the dealer knew of your intended use, the school should contact NHTSA's Office of Vehicle Safety Compliance, at the address given above, and inform them of the apparent violation of federal law. In the past, many dealers who have been notified by NHTSA of the illegality of selling noncomplying vans as school vehicles repurchased the vehicles that were sold in violation of the law. However, these instances involved essentially new vehicles. Section 154(a)(2)(A)(iii) of the Safety Act specifies the repurchase remedy as, 'the purchase price of such motor vehicle in full, less a reasonable allowance for depreciation' (emphasis added). Thus, it may be more cost efficient for the school district to use these vans for other purposes within the district or transfer them to other county functions. For future vehicle purchases, it may be advisable to inform dealers specifically that the vehicles will be used for transporting school children. I hope you find this information helpful. If you have further questions, please contact Mary Versailles of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.