Pete Hornberger steps into traffic

I was riding in a car with a few people in the late evening in drizzling rain, in a city — seemed like Washington DC at first, but probably was New York City. We were stopped at a red light, with the road sloped down behind us. To our right, the cross street had a narrow concrete median (on the right side of the road), and standing on the median was Pete Hornberger from 30 Rock.

He was holding a smallish white sign with something written on it, and was peering out towards the oncoming traffic (he was facing our direction). He shouted a few times, apparently towards somebody off in the distance to our left. He kept taking a few steps out into the road and looking off in the distance, and then coming back to the median because of the oncoming cars.

I didn't understand what he was trying to do, and told my friend so, and she mentioned that he might actually be shooting a scene for the show right now. That actually made sense to me, so I stopped worrying about it.