The EPA Urban Dynamometer Driving Schedule (UDDS) has been developed for chassis dynamometer testing of heavy-duty vehicles [CFR 40, 86, App.I]. It is sometimes referred to as “cycle D”. The HD-UDDS cycle should not be confused with the FTP-72/LA-4 cycle for light-duty vehicles, which is also termed UDDS.
Figure 1. HD-UDDS Cycle
The following are basic parameters of the cycle:
- Duration: 1060 seconds
- Distance: 5.55 miles = 8.9 km
- Average speed: 18.86 mi/h = 30.4 km/h
- Maximum speed: 58 mi/h = 93.3 km/h
The UDDS schedule was a basis for the development of the FTP transient engine dynamometer cycle.