“Increase and Maintain Predictability” is one of the three objectives identified in the Mobility Performance Framework. These objectives specify how WSDOT seeks to achieve Washington State’s desired mobility outcome: To improve the predictable movement of goods and people throughout Washington State, including congestion relief and improved freight mobility.

Predictability is defined as “consistency of travel time and experience by mode, including measurement of congestion as well as options to avoid congestion.” WSDOT uses two categories of predictability performance measures:

Travel Reliability: Reliability is important for highway users because it provides information that allows travelers to plan for on-time arrival with a higher degree of certainty. Commuters can plan their daily trips to work during peak hours, parents can plan their afternoon run to the daycare center, businesses know when a just-in-time shipment must leave the factory, and transit agencies can develop reliable schedules.

Network Resiliency: Network resiliency addresses the availability of route and mode options to avoid closures and delays. Factors include fluctuations in normal traffic, bottlenecks (chokepoints), traffic incidents, weather, work zones, signal timing, special events, ferry traffic, and influence of local land use activities.