[Code of Federal Regulations]
[Title 49, Volume 4]
[Revised as of October 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 49CFR393.78]

[Page 1132]
 
                        TITLE 49--TRANSPORTATION
 
        CHAPTER III--FEDERAL MOTOR CARRIER SAFETY ADMINISTRATION,
                      DEPARTMENT OF TRANSPORTATION
 
PART 393--PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION--Table of Contents
 
             Subpart G--Miscellaneous Parts and Accessories
 
Sec. 393.78  Windshield wipers.

    (a) Every bus, truck, and truck tractor, having a windshield, shall 
be equipped with at least two automatically-operating windshield wiper 
blades, one on each side of the centerline of the windshield, for 
cleaning rain, snow, or other moisture from the windshield and which 
shall be in such condition as to provide clear vision for the driver, 
unless one such blade be so arranged as to clean an area of the 
windshield extending to within 1 inch of the limit of vision through the 
windshield at each side: Provided, however, That in driveaway-towaway 
operations this section shall apply only to the driven vehicle: And 
provided further, That one windshield wiper blade will suffice under 
this section when such driven vehicle in driveaway-towaway operation 
constitutes part or all of the property being transported and has no 
provision for two such blades.
    (b) Every bus, truck, and truck tractor, the date of manufacture of 
which is subsequent to June 30, 1953, which depends upon vacuum to 
operate the windshield wipers, shall be so constructed that the 
operation of the wipers will not be materially impaired by change in the 
intake manifold pressure.