Forgotten Tunnel Under Union Turnpike

I discovered this long sealed up tunnel on 1/1/12 by accident. I have driven over it hundreds of times and never knew it, so maybe you did too. I have discerned that it was once an on ramp to the GCP, but was considered obsolete as well as unsafe and sealed off many years ago. I theorize it was shut back in the 40s or early 50s and was recently broken into by vandals.