UKMARS line follower tracks are printed on PVC sheet. Unfortunately, suppliers seem to either quote the material thickness in microns (mic) or its weight in grams/square metre (gsm)
The material we use is typically 550gsm or 220mic and courses are usually designed to fit on standard sheet sizes like A0 (84.1 cm wide × 118.9 cm) or double A0 (118.9 cm × 168.2 cm)
Note that the so-called half-size test tracks can be printed at double size to make a classic line follower layout.
Heavier 400mic sheet will be more durable and may not be significantly more expensive. You may find this thickness described as 700gsm or double-sided.
There are many suppliers for these kinds of products and prices can vary a lot. Search for PVC banner printing to find suppliers convenient for you.
Download pdf files of line follower tracks from these links: