I think what I'm going to do is use a peice of rope the width of the lanes and jam as much length into the shape as I can. I have just a few restrictions if anyone wants to help.

Upside down L with the top being 90 feet across the top and then 60 feet down the right side. Going left along the bottom is 60 feet and then up the inside of the L is 30 feet, tun left for another 30 feet and then up the left side is 30 feet.

I want to stand at the inside bevel of the L so I can see both directions of the L and I also want it to be a figure 8 with the cross-over designed so that the long length of straaightaway jumps over the short side. The short side (underside of the 8) is lined up with the driver standing at the inside of the L so driver can visibly see the car/truck coming thru the underpass. The rest is pretty open and I like the max length of straightaways as possible.