Making a Track in SketchUp
Fire up SketchUp
Zoom out some
Draw a big rectangle. It will be BLUE. THAT IS BAD. BLUE is the wrong side.
Select it and right mouse-click and 'Reverse Faces'
Now it'll be WHITE. That's what you want to see. NO BLUE!
Gonna make a quick oval track. Draw a circle.
Select it. Hold down CTRL and drag to clone it.
Connect the two with LINE tool. Connect at the ENDPOINTS. Hover over circle and ENDPOINTS will be highlighted
Remove inner arcs.
Select inner section and use OFFSET tool to make the 'road'.
Connect the ENDPOINTS again to break up the curve.
Use PUSH/PULL tool to raise middle

Create a new MATERIAL and IMPORT your road TIFF.
Change the name from "MaterialX" to something meaningful.
This where you can change the SCALE of the texture.
Use the PAINTBUCKET to apply texture. Oh oh, needs to be rotated 90'
Right mouse-click on the texture.
Rotate 90.
That's better. Follow this tute to lay down the road.
If you want a shoulder on the road...
Use PUSH/PULLto raise middle. Use SCALE tool to bring it in.
Like so.
Repeat the steps to map the road to map a "road edge" around the track
SCALE the middle bring it in further.
Add some grass..
Voila! Down and dirty oval track.