The Highway Fuel Economy Test (HWFET or HFET) cycle is a chassis dynamometer driving schedule developed by the US EPA for the determination of fuel economy of light duty vehicles [40 CFR 600, subpart B]. The HWFET is used to determine the highway fuel economy rating, while the city rating is based on the FTP-75 test.
Figure 1. EPA Highway Fuel Economy Test Cycle
The test is run twice, with a break of maximum of 17 s between the runs. The first run is a vehicle preconditioning sequence, the second run is the actual test with emission measurement.
The following are some characteristic parameters of the cycle:
- Duration: 765 seconds
- Total distance: 10.26 miles (16.45 km)
- Average Speed: 48.3 mi/h (77.7 km/h)