Lyric discussion by gun left behind 

Cover art for Gridlock Caravans lyrics by Death Cab for Cutie

I think this song is about feeling different from other people - whether it be through experiencing love when others haven't, having an epiphany about life, or whatever. But you press your shirts and feel all clean and enlightened, and you think everything's going to work from here on out but it only gets worse since you become distant and can't find anyone to relate to.

This song is probably about love, since he talks about his heart being too heavy for his chest to hold as if he's just been overwhelmed with emotions and that's what makes him feel distant, like no one else knows what he's known or how he's felt.

I wish I knew what he was talking about lighting, something with plastic at one end. But the last few lines are about the distance he feels; the "friends" he has, who are supposed to understand him, are on the exit ramps to gridlock caravans; they're all getting off but there's no stopping the train he's on and the farther away they go the more muffled their voices become. Until finally you can't even talk to them anymore because the metal of the caravan and the thick glass of the windows drowns out the sound.

Whatever this song is about though, there's that hint of genius. One of Death Cab's best, for sure.