US: Heavy-duty: BAC

US: Heavy-duty: BAC


The Transit Coach Operating Duty Cycle was originally designed to measure heavy-duty vehicle’s fuel economy (SAE J1376, canceled 1997).


This cycle, also referred to as Business-Arterial-Commuter (BAC) to reflect its composite character, includes a sequence of segments performed on a chassis dynamometer:

  1. Central Business District (CBD) segment
  2. 300 second idle period
  3. Arterial segment
  4. CBD segment
  5. Arterial segment
  6. CBD segment
  7. Commuter segment



Composite BAC Cycle


CBD Segment


Arterial Segment


Commuter Segment


The following are characteristic parameters of the composite BAC cycle:

  1. Duration: 2830s
  2. Driving distance: 22.53 km
  3. Maximum speed: 88.5 km/h (55 mph)
  4. Average speed: 28.9 km/h

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