We were ahead of it initially but they were catching up as people pulled to the side to let them pass (as you're supposed to with flashing lights). We also pulled to the right side as they got closer but they changed from overtaking to 'flushing' cars ahead of them even though they had room to get through. Everyone was confused and it mucked up traffic for a bit. Eventually they decided again that it was time to pass vehicles again which is when we finally realized what they were escorting on the Oversized Load truck. Hope you didn't get stuck behind it for too long. We pulled off to go to H-mart but were with it for a while, since Journal Square-ish. Drawing a blank as to what that end of 1-9 is called for some reason.