VAC (visibility-adjusted contact)

VAC stands for visibility-adjusted contact: an out-of-home impression that has been corrected for how likely people were to actually see the ad, not just pass near it.

Raw impression counts treat every passer-by the same. VAC does not: it weighs each contact using factors like the screen’s size and position, the viewing distance and angle, how fast people move past, and how long the ad was on screen. A large screen facing slow foot traffic scores higher than a small one seen sideways from a fast road.

The point is fair comparison. Two screens can claim the same traffic while offering very different real visibility, and VAC-based figures make out-of-home audiences more realistic and closer to how other media count their contacts.