Cycle Time
The following excerpt was taken from the Transit Cooperative Research Program
(TCRP) Report 30, page 19.
Cycle time is the number of minutes needed to make a round trip on the route, including
layover/recovery time. Cycle time is important for several reasons, including playing a
part in the formula used for determining the number of vehicles needed to provide a given
level of service on a route.
Since cycle time equals the number of minutes needed to make a round trip, including
the layover/recovery time, the scheduler determines the amount of time it takes to operate
or "run" from one end of the route to the other and back, then adds
layover/recovery time to yield the cycle time.
Minimum vs. Available Cycle Time
For many agencies, on some or all routes, the amount of layover/recovery time is often
determined by labor agreement or agency policy. These agreements or policies dictate a
minimum number of minutes that must be built into the schedule for layover/recovery.
Minimum cycle time is the number of minutes scheduled for a vehicle to make a round
trip, including a minimum layover/recovery time as dictated by labor agreement or agency
policy . . . . However, maintaining a constant headway . . . will, in most cases, result
in a cycle time other than the minimum cycle time for the vehicles operating that route .
. . . The resulting cycle time (which includes the additional layover/recovery time)
necessary to maintain the 30-minute headways is now called the available cycle time. In
the optimal case, the minimum cycle time would be the same as the available cycle time.
However, maintaining fixed, clock multiple headways often makes that impossible.
|