According to the MTA, graffiti writers aren’t bombing trains and tunnels in NYC nearly as much as they used to, with the amount of vandalism dropping by more than half in the past few years. The Daily News credits the decline to the transit agency’s anti-graffiti unit known as the Eagle Team and their increased participation with the NYPD.

This reduction means less cleanup costs and apparently, could potentially keep the city safer from terrorists. “When fighting graffiti and vandalism post 9/11, you’re not just fighting graffiti and vandalism. The reality is if a bunch of kids who vandalize trains can breach security, bad guys intending to do much worse also can breach security,” said MTA Security Director Vincent DiMarino.