Marty himself is about to respond about Einstein when he also notes the car, listens to the cop. The cop that talks about curfews and goggles apparently being regulation. What goggles? But he doesn't say anything, doesn't get the chance to or want to make it worse by questioning her further before she drives off again.

After which he gives Doc a Look. One he probably knows all too well, given Marty's almost perpetual confusion and feeling over his head each time they've traveled through time at least at some point in their adventuring.

"Well. That explains how quiet the streets are. No idea what she meant about the goggles but I guess we'll have to figure something on that before we head back here tomorrow?"