Credits are the single currency in the Carmageddon universe. They could also be considered as a points score.
Credits can be obtained trough a variety of ways, such as killing pedestrians, passing trough checkpoints and wasting opponents. These are the basic methods, but there are still other options, like earning bonuses and collecting pickups.
Credits are earned according to play style. For instance, completing a race by merely wasting every opponent and hardly touching the peds and checkpoints isn't going to give the player much wealth. Playing with style may be the best for the player; for instance, it may be better to spend just a little bit of afterburner to complete the twist and earn a cunning stunt bonus.
At the end of a race the player is given two bonuses; a time bonus, depending on how much was on the timer when the race finished, and a completion bonus, that varies between completion modes. Also, different difficulty levels grant different amount of credits in most situations.
All these credits are earned to be spent, not on leisure objects, but on the car. The player spends credits each time (s)he repairs, recovers, etc. But the credits are mostly spent on upgrading the APO and buying new vehicles. There is a fine for skipping the countdown.
As a powerup
In the games
The credit amount is global, but when in-race, it's relative. This means that the player has either a certain amount of profit or loss. When the race is finished, that value is added/removed to the global credits.
Unlike the first game, the credits are always global. In a race, if the player ends up losing way to much credits, an APO part is immediately sold to receive more cash. If the player ends up with 0 credits and 0 APO, all things are still charged, but the money will not decrease.
The credits are identified with $ in the menus, but not anywhere else. This is either the symbol for the fictional currency, or it could be a mistake (the $ standing for US Dollars).
As with TDR 2000, the currency is defined as $ (presumably US Dollars).