One caveat to all of this: Since most interstates exhibit asymetric
shoulder widths - it would be tough to judge the actual center of the
pavement. You can't just land in the center of the two traffic lanes.

While true, it's not a big deal (IMHO, who has never landed on an
interstate). The difference in shoulder width is just a few feet (I
have driven them), and half that is all you need to stay left of the center.

Jose

--
Money: what you need when you run out of brains.
for Email, make the obvious change in the address.