Transportation Research Interdisciplinary Perspectives (May 2023)
The overlooked transport project planning process — What happens before selecting the Locally Preferred Alternative?
Abstract
This study investigates the transport investment decision process of judging the robustness and viability of the selected option compared with the rejected alternatives.This paper adopted the Ridership to Cost Ratio (RCR), that is analogous to the Benefit Cost Ratio (BCR) and contrasts the unit cost at which the proposed transit alternative can serve one additional transit patron, as the primary measure of assessing the relative advantage of alternatives.We found that on average the ‘do-minimum’ option generates a Ridership to Cost Ratio (RCR) nine times higher than the Locally Preferred Alternative (LPA), and the average RCR produced by the second-best alternative is 86% higher than that of the LPA, indicating substantial opportunity costs of rejecting more economical course of action which could have likely managed prospective demand at much lower costs and delivered more services for more people at the same budgetary outlay. Second, we observed that the primary factor differentiating build alternatives is route alignment. However, ridership estimates for alternatives with different routes show narrow differences, raising concerns about whether the existing user benefit assessment framework can fully exploit potential values credited to each alternative option. Third, the number of alternatives considered in the Draft Environmental Impact Statement has gradually declined across the past three decades, informing that the identified transport problems are prone to be approached from confined terms of reference. Last, most projects only compared the preferred light rail mode against the traditional bus mode in the Transportation Systems Management (TSM) base option, attesting to concerns about selection bias and discrimination in early-stage appraisal and decision-making.
