Why do some people move over or slow down when overtaking a parked police vehicle using flashing lights?

Section 3327 of the Pennsylvania Vehicle Code requires the drivers of all vehicles approaching or passing an emergency response area to move to an adjacent lane of travel, or if not possible, legal, or safe to do so, slow down to a careful and prudent speed for the conditions.  The law defines emergency response areas in include police officers conducting traffic stops.  The law also protects all emergency service providers rendering assistance to individuals on or near a roadway.  Remember to move over, slow down, or do both, to help save a life!