Where do airports use 3-bar VASI for the visual glideslope?
Runway 8 at Albuquerque International Sunport Airport (KABQ) has a 3-bar VASI.

KABQ's current Chart Supplement page1 lists the VASI for Runway 8 as a VASI(V6L): a 3 bar, 6 box VASI located on the left side of the runway. The airport diagram also depicts the VASI as a V3: a three-bar VASI. 


The VASI bars are also visible in aerial images, such as here on Google Maps:





1The current Chart Supplement page will expire and this link will be broken. For future reference, the updated Chart Supplement page can be found elsewhere, such as on this SkyVector page.