As long as it doesn't have a brass knuckle type handguard, you can have any type any length fixed blade in your car, open or concealed. The only law regarding fixed blades is that you cannot conceal one on your person, so even a 2" neck knife under your shirt is illegal.
------------------
Jason aka medusaoblongata
-----------------------
"I have often laughed at the weaklings who call themselves kind because they have no claws"
- Zarathustra