A heuristic framework for exploring uncertainties in transport planning

Book of proceedings: Annual AESOP Congress, Spaces of Dialog for Places of Dignity, Lisbon, 11-14th July, 2017In recent decades, the effectiveness of positivistic approaches in transport planning has been growly contested by academics and practitioners (Innes and Booher, 2010). The idea of planning for a single model of reality is becoming obsolete when considering the fast and radical changes that society is experiencing at present and in the near future (e.g. ICT advances, environmental concerns, social inequalities, changes in mobility behaviour, etc.) (Batty et al., 2012; Lyons and Davidson, 2016; Marsden et al., 2014). The discussed crisis of the rational-planning model has generated a great deal of interest in those rationalities pursuing “alternative realities” of planning, rooted in critical realism, constructivism and pragmatism (Khisty and Arslan, 2005). However, practitioners and policy-makers are still comfortable with the idea of planning as “enlightening the future”, also reinforced by traditional planning cultures, legal frameworks, and political institutions (Lyons and Davidson, 2016). Placed in a crossroad of approaches, motivations and perspectives, the issue of unveiling uncertainty has been gaining relevance among transport-planning researchers (Martens and van Weelden, 2014). Attempts at understanding uncertainty have mostly been made from a decision-making perspective, especially from the transport-modelling field (van der Pas et al., 2010; Walker et al., 2003). However, those approaches face what is known as the “uncertainty paradox”: the recognition of higher levels of uncertainty goes hand in hand with the expectations of positivistic science and knowledge to tackle them (van Asselt and Vos, 2006). Moreover, despite multiple dimensions of uncertainty having been explored in literature (Brown, 2004), they seldom encompass the plurality of perspectives (and also languages) involved in transport planning. At this point, previous systematization and conceptualization efforts need to converge into common overarching frames, which are flexible enough to embrace this plurality of uncertainty dimensions.Published versio