Sleeper buses are harder to make survivable than seated ones, because a passenger lying down cannot brace, cannot be restrained the way a seated occupant is, and in a fire has to get out of a horizontal compartment rather than simply stand up and walk. AIS-153, mandatory since September 2025, is the regulatory response - it tightens structural strength, fire performance and emergency egress for longer buses, with more exits required above 12 metres. Certifying a 15-metre multi-axle sleeper is therefore not merely a length record. It establishes that a body configuration at the upper end of what Indian rules permit can be built to the new construction standard, which opens the way for higher-capacity intercity coaches on a route network where operators have been adding length to cut cost per passenger.

The National Automotive Testing and R&D Infrastructure Project was approved by the Cabinet Committee on Economic Affairs in July 2005 and is run under the Ministry of Heavy Industries. Its purpose was to give India testing infrastructure of a standard that would let vehicles be certified domestically rather than abroad, and it produced ICAT at Manesar, GARC near Chennai and NATRAX at Pithampur, alongside upgrades at existing centres such as ARAI, Pune, VRDE, Ahmednagar and NIAIMT, Silchar. In practice a manufacturer or bus body builder submits a prototype to one of these designated agencies, which tests it against the applicable Automotive Industry Standards and, if it conforms, issues the compliance or type-approval certificate that permits series production and registration. The AIS documents themselves are drafted through the Automotive Industry Standards Committee with ARAI as secretariat, and are notified for enforcement under the Central Motor Vehicles Rules by the Ministry of Road Transport and Highways.