Download the Code of Federal Regulations in XML.
The Electronic Code of Federal Regulations (e-CFR) is a regularly updated, unofficial editorial compilation of CFR material and Federal Register amendments produced by the National Archives and Records Administration's Office of the Federal Register (OFR) and the Government Publishing Office.
Parallel Table of Authorities and Rules for the Code of Federal Regulations and the United States Code
Text | PDF
Find, review, and submit comments on Federal rules that are open for comment and published in the Federal Register using Regulations.gov.
Purchase individual CFR titles from the U.S. Government Online Bookstore.
Find issues of the CFR (including issues prior to 1996) at a local Federal depository library.
Electronic Code of Federal Regulations
Title 40: Protection of Environment
§51.355 Test frequency and convenience.
(a) The performance standards for I/M programs assume an annual test frequency; other schedules may be approved if the required emission targets are achieved. The SIP shall describe the test schedule in detail, including the test year selection scheme if testing is other than annual. The SIP shall include the legal authority necessary to implement and enforce the test frequency requirement and explain how the test frequency will be integrated with the enforcement process.
(b) In enhanced I/M programs, test systems shall be designed in such a way as to provide convenient service to motorists required to get their vehicles tested. The SIP shall demonstrate that the network of stations providing test services is sufficient to insure short waiting times to get a test and short driving distances. Stations shall be required to adhere to regular testing hours and to test any subject vehicle presented for a test during its test period.