Passenger Seats. The minimum clearance of all aisles, including the aisle or passageway between seats leading to the emergency door, shall be 12 inches. The forward-most seat on the right side of the vehicle shall be located so as not to interfere with the operator's vision and may not be farther forward than the rear of the operator's seat when adjusted to its rearmost position. A minimum of 36 inches of headroom for the sitting position above the top of the undepressed cushion line of all seats shall be provided. Measurement shall be made vertically not more than 7 inches from the side wall at cushion height and at the fore and aft center of the cushion. The backs of seats of similar size shall be of the same width at the top, of the same height from the floor, and shall slant at the same angle with the floor. Seats shall be: Forward facing and shall be securely fastened with bolts and nuts to supporting parts of the vehicle. Each leg shall be fastened with a minimum of two bolts and nuts. Portable seats are not acceptable. Aisles between forward facing seats shall have a minimum clear width of 12 inches; and As of January 1, 2014, all vehicles procured for use in this State shall be constructed with materials that enable it to meet all the criteria of the school bus seat upholstery fire block test established by the National School Transportation Specifications and Procedures adopted at the most recent National Congress on School Transportation. Aisle supports of seat backs shall be slanted away from the aisle sufficiently to give an aisle clearance of 15 inches at the tops of the seat backs. The rear davenport paneling shall be covered with fireblock upholstery or have fireblock material between the engine compartment and the passenger compartment, and the seat on rear engine busses shall be covered with fireblock upholstery. As of January 1, 2014, all vehicles procured for use in this State shall be constructed with materials that enable it to meet all the criteria of the school bus seat upholstery fire block test established by the National School Transportation Specifications and Procedures adopted at the most recent National Congress on School Transportation. A flip-up seat may be installed at side emergency doors. Track Seating. Track seating may be used. The top of the track shall be flush with the floor. The manufacturer shall install a label to indicate the required seat spacing. Bolts, nuts, and washers or flanged-head nuts shall be used. Operator's Seat. The minimum distance between the steering wheel and the backrest of the operator's seat is 11 inches. The operator's seat shall: Be rigidly positioned; Have vertical adjustment and fore and aft adjustment of not less than 4 inches, without the use of tools or other devices; Be fastened to the floor with bolts, nuts, and washers or flanged-head nuts; and Be covered with Fire-Block material. As of January 1, 2014, all vehicles procured for use in this State shall be constructed with materials that enable it to meet all the criteria of the school bus seat upholstery fire block test established by the National School Transportation Specifications and Procedures adopted at the most recent National Congress on School Transportation. Crash Barriers. Crash barriers shall be located on both sides of the aisle in front of the most forward facing seat. On vehicles with the engine inside the front of the body, the minimum distance between the barrier at rear of the entrance step-well and the engine cover shall be 14 inches at floor level. Barriers shall be covered with Fire-Block material. As of January 1, 2014, all vehicles procured for use in this State shall be constructed with materials that enable it to meet all the criteria of the school bus seat upholstery fire block test established by the National School Transportation Specifications and Procedures adopted at the most recent National Congress on School Transportation. Sun Visor. An interior adjustable transparent sun visor not less than 6 inches wide and 30 inches long shall be installed so that it can be turned up to prevent being a hazard when not in use. It shall be supported by two brackets. Steering Wheel. The steering wheel circumference shall have at least 2 inches of clearance at all points. Speakers. Ceiling or side-mounted speakers shall be flush mounted.