From the state manual for obtaining your commercial driver's license.
"Vehicles over 8300 GVWR and exceeding 78 inches in height require operating yellow or amber cab marker lights when operated between official sundown and sunrise times. Cab marker lights must be located no more than 22 inches laterally from the top of the windshield."
http://www.nydmv.state.ny.us/broch/cdlmanual.htm