Cheat mode
Enter "ZAKARY X" as a name to unlock all trucks and cheat options.

Faster vehicles (alternate)
Note: This procedure involves editing a game file; create a backup copy of the file before proceeding. Enter the "vehicles" sub-directory inside the game directory. Use a utility such as WinZip or PKUnzip to extract the "physics.txt" file from any of the .zip files. Use a text editor to edit the "physics.txt" file and change the "//idealMaxSpeed" entry to "200". Save the file and add it back to the original .zip file. The top speed bar will be full for the vehicle when the game is played.