A similar condition can occur on the Urban Street analysis. As such, the multi-period analysis can account for the impact of queues while forming and dissipating, providing a comprehensive view toward facilities operational condition.
When a facility is under capacity, both peak period and multi-period analysis will report the same results! However, when traffic condition is oversaturated, peak period analysis will generate a misleading result. It is always advised to evaluate the operational condition of the analysis to determine if there are queues or not, then, based on that, pick the correct type of analysis. Of course, a multi-period analysis can always be used, regardless of traffic condition, to estimate performance measures.
In summary, the recommended analysis approach is:
- For undersaturated conditions (LOS E or better), peak period analyses provide a reasonable estimation of performance with a small amount of required effort
- For oversaturated conditions (LOS F), multi-period analyses must be used to account for the effects of queueing in freeways
The HCS will prompt a warning message when the analysis condition requires a multi-time period analysis. The following image shows an example warning message where the oversaturated condition exists in a single analysis period (peak period analysis).