Section 35406 does not apply to the booms or masts of shovels, cranes or water well drilling and servicing equipment carried upon a motor vehicle if the following conditions are met:

1. (a) The booms or masts shall not extend more than two-thirds of the wheelbase beyond the front tires of such vehicle.
2. (b) The projecting structure or attachments thereto shall be securely held in place to prevent dropping or swaying.
3. (c) No part of the structure which extends beyond the front tires shall be less than seven feet from the roadway.
4. (d) The driver’s vision shall not be impaired by the projecting or supporting structure.