What do transit improvements do to increase accessibility for people and businesses? How can accessibility be quantified to compare transit alignments and modes? How can technical staff effectively communicate the concept of transit accessibility to policy-makers and the public? Can we measure transit’s impact through access as well as ridership?
The Bottineau Transitway Alternatives Analysis evaluated LRT and BRT in a 13-mile dedicated runningway from Minneapolis, Minnesota to its northwest suburbs. The planned corridor includes large populations of people with no personal vehicles in their households and in households with low incomes. The region sought to understand and communicate whether the alternatives would yield significant accessibility differences for corridor residents and businesses, including differences for specific travel markets within the corridor. Investigation of accessibility measures helped to lend credibility to aggregate ridership results, and link ridership more directly to service changes. The travel demand forecasting results convinced local decision-makers that a transit market exists in the corridor, that it is a large market even if a small share of the corridor’s overall travel market, it is a market with needs warranting light rail transit, and overall accessibility differences among alternatives were not significant.
The paper discusses the transit accessibility metrics, results, and lessons learned through travel demand forecasting for the Bottineau Transitway. Key challenges in defining the metrics were isolating and understanding effects of small changes in light of the nature of rail service with particular access points and stop locations, and the nature of zone-based transportation models; valuing of out-of-vehicle time; and handling mode-specific constants. Confidence in the travel demand forecasting results was the key challenge in using them. The key challenges in communicating the analysis results were presenting cumulative opportunity measures concisely, presenting the information in meaningful ways that acknowledge the implicit value assumptions and highlight them for policy discussion and reminding people the results reflect their physical, not psychological experience, with transit. In addition to articulating the challenges with analyzing and communicating transit accessibility, the paper will highlight the value of sub-market analyses in transit forecasting.