Where a taxiway crosses a runway, or where a "lead-off" taxiway centreline leads off of a runway to join a taxiway, these lights will alternate yellow and green. Clearance Bar Lights: Three in-pavement steady-burning yellow lights installed at holding positions on taxiways Runway Guard Lights: Either a pair of elevated flashing yellow lights installed on either side of the taxiway, or a row of in-pavement yellow lights installed across the entire taxiway, at the runway holding position marking at taxiway/runway intersections. Stop Bar Lights: A row of red, unidirectional, steady-burning in-pavement lights installed across the entire taxiway at the runway holding position, and elevated steady-burning red lights on each side used in low visibility conditions (below 1,200 ft RVR).