Transit Coach Operating Duty Cycle (BAC)

Time-speed data points: CBD | Arterial | Commuter

The Transit Coach Operating Duty Cycle, Figure 1, was originally designed to measure heavy-duty vehicle’s fuel economy (SAE J1376, cancelled 1997). This cycle, also referred to as Business-Arterial-Commuter (BAC) to reflect its composite character, includes a sequence of the following segments performed on a chassis dynamometer:

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

The following are characteristic parameters of the composite BAC cycle:

• Duration: 2830 s
• Driving distance: 22.53 km
• Maximum speed: 88.5 km/h (55 mph)
• Average speed: 28.9 km/h