40 CFR §205.55-3
- (a)A separate vehicle configuration shall be determined by each combination of the following parameters:
- (1)Exhaust system configuration.
- (i)Single vertical.
- (ii)Dual vertical.
- (iii)Single horizontal.
- (iv)Dual horizontal.
- (2)Air induction system (engine).
- (i)Natural.
- (ii)Turbocharged.
- (3)Fan.
- (i)Diameter.
- (ii)Drive.
- (a)Direct.
- (b)Thermostatic.
- (iii)Max fan rpm.
- (4)Engine manufacturer's horsepower rating.
- (5)Cab characteristic.
- (i)Sleeper.
- (ii)Non sleeper.
- (6)Category parameters listed in § 205.55-2.