Abstract Manager

In a significant portion of transit infrastructure decisions, choices and outcomes relating to an investment are dependent on the realization of other projects or implementation of new policies. An oft-cited example of this phenomenon is the frequently-lauded decision to include a lower level on Toronto's Prince Edward Viaduct when it was constructed in 1918, successfully future-proofing for Toronto's east-west subway line, opened in 1966. In other words,  there are two ways - single decked or doubled decked -  to build Investment A (bridge), which is funded and in delivery. Investment B (subway) is in the planning stages and is uncertain. If Investment B is built in the future, Investment A should be optimized to support and connect (including the lower level). However, if Investment B (the subway) is never built, designing Investment A (the bridge) to support and connect is higher cost and sub-optimal. This type of interdependent decision repeats over and over in transit planning but is rarely recognized as an archetype. Because these interdependent decisions are not recognized as part of a pattern, analytic tools to support decisions are not well established, resulting in risk of sub-optimal decisions and unnecessary spending. This presentation will examine and define this problem archetype, provide examples, and then explore methodologies for analysis, adapted from other decision-making frameworks that offer promising in addressing this novel context. In particular, the "Decision Making Under Deep Uncertainty" framework, which is often used to support infrastructure decisions amidst climate uncertainty, offers a promising methodology. Risk assessment tools and cost-benefit analysis may also serve as part of a toolbox. Ultimately this presentation will discuss a novel problem that will likely be familiar to many in the audience and will offer potential analytical frameworks that transportation professionals can use to support improved decision-making.