In MENUDATA\PARTDB and GAMEDATA\COMMON, there's a file named DRIVERS.DDB. (Not the DirectX DRIVERS.DDB, haha.)
I experimented with it some time ago, and have it mostly figured out. Here's a snippet of Rocket Racer's entry, with added comments:
k_27 // Driver
"RR"
{
k_33 // ID? Does it need this?
0
k_29 // Driver GDB
"rrpelvis"
k_28 // Driver MDB
"rrpelvis"
k_2A // Driver TDB
"rrpelvis"
k_