A key element of any transit corridor study is determining reasonable, yet competitive travel times for transit alternatives. Travel time estimates for premium transit services (e.g., heavy rail, light rail, commuter rail, bus rapid transit) are typically hard-coded in a regional travel demand model. These travel times influence ridership forecasts, vehicle requirements and transit service hours, which ultimately determines O&M costs.

The primary components in building a transit travel time estimate are:

• Speeds (while vehicle is in motion)

• Alignment (e.g., horizontal curves and vertical grades)

• Traffic signals (for alignments not in exclusive right-of-way)

• Station or stop dwell times

• Traffic congestion (for alignments operating in mixed traffic conditions)

Speeds are influenced by acceleration and deceleration rates, which vary by transit mode. Alignment considerations are typically identified in project plan and profile drawings that identify curve radii, track super elevation and vertical grades. Traffic signal delays depend on traffic signal characteristics (signal cycle length, green time allocation, whether or not there is transit signal prioritization). Station or stop dwell times are most influenced by station boarding volumes. Finally, traffic congestion can vary significantly by time-of-day and location along the proposed transit alignment.

The level of information available for each of these influencing components is directly related to the stage of project development. A feasibility study is likely to have very limited information on these elements, whereas a project in final design should have fairly clear definitions for each of these components.

This presentation will present a planning process for building a transit travel time estimate with reasonable assumptions for each of these transit travel time components. This presentation will identify typical acceleration and deceleration rates for different transit modes, appropriate planning level assumptions for estimating traffic signal delay, potential transit travel savings gained with transit signal prioritization, typical station and stop dwell times (including impacts associated with off-board fare collection) and planning level assumptions to account for time-of-day traffic congestion.