The headlight assemblies for the Freightliner Cascadia truck (CPBP 34-009-V2-S) has adjusters located at the back of the housing, which can be turned clockwise/counter clockwise to adjust the light to the optimal angle.
Please refer to the picture below for the location of the adjusters.
Link to the referred item: http://www.niuparts.com/freightliner-cascadia-headlight-driver-passenger-side.html