A while back I made a set of texture templates that I used to make some evo2 tracks.
If you have spent any time here. http://cownap.com/~mtmg/templates/
Then you have read about the problems with the diagonals when trying to make opposite entry and exit turn directions.
The diagonals I have made solve this problem. The trick with them is to mix and match ends to get the entry exit direction you need, the center section of each diagonal will tile to create a straight in the direction of the diagonal used.
The full set includes 4 sizes of curves , that, other than width, are exactly like section 11 of the texture page above. Crossroad, and the above diagonals that are in 4 configurations. All will join with each other seamlessly. As long as your textures are, of course.
You can get the templates here.
If your registered at our forum, or wish to register to see the post I left there about them. Go here
or get the .pdf file
(right click, save target as, to prevent from loading in your browser if desired)
Its not the most detailed, but with the texture page and this you can get the basic idea.
I'll be happy to help with any questions you have.