DIY sound block layer on window?

[fmincon]

I live in an apartment that faces a major road and train station, so the traffic noise is quite bad in my bedroom.  Most of the noise seems to be seeping through the only window in the bedroom (which is right next to my head when I sleep).  Is there any cheap way to block the sound coming in, maybe with some sort of material that I could just tape over the entire window?  Replacing with a whole new window isn't a viable option in my case.

[Greg]

A thick cloth curtain is probably your best bet.  Assuming you sleep with the window closed because of the noise, check that it's tight closing and perhaps use caulking on any cracks.

[Left]

get some bubble wrap, roll it into a roll and pack/tape it into window frame works for me. It helps insulate it for winter too