(a) The FTP driving cycle is prescribed in § 86.115 of this chapter.
(b) The highway fuel economy driving cycle is specified in this paragraph.
(1) The Highway Fuel Economy Driving Schedule is set forth in appendix I of this part. The driving schedule is defined by a smooth trace drawn through the specified speed versus time relationships.
(2) The speed tolerance at any given time on the dynamometer driving schedule specified in appendix I of this part, or as printed on a driver's aid chart approved by the Administrator, when conducted to meet the requirements of paragraph (b) of § 600.111 is defined by upper and lower limits. The upper limit is 2 mph higher than the highest point on trace within 1 second of the given time. The lower limit is 2 mph lower than the lowest point on the trace within 1 second of the given time. Speed variations greater than the tolerances (such as may occur during gear changes) are acceptable provided they occur for less than 2 seconds on any occasion. Speeds lower than those prescribed are acceptable provided the vehicle is operated at maximum available power during such occurrences.
(3) A graphic representation of the range of acceptable speed tolerances is found in § 86.115(c) of this chapter.