PIAA 004 Series - Manual (Page 6)

DRIVING LIGHT
AIMING
Typically, driving lights are mounted above the front bumper about 14-30 inches
from the ground to provide extra high beam illumination. Driving lights can be
mounted below the bumper, although they will not be as effective because the
light will hit the ground sooner and reduce the range of the light.
Visual aim is made with the center of the beam hot spot 1.5 inches below the
lamp center at 25 feet with the lamp facing straight forward. (see below.)
Do not use driving lights into oncoming traffic.
Driving lights should never be the only foreword light source.
Driving lights should only be used with the headlamp high beams.