Determining trip attraction rates for the UK office developments with limited observations and missing data

Development planning decisions are heavily reliant upon expensive and relatively scarce trip rate information data. With a view to curtailing excessive car use, development planning decisions must be made irrespective of how sparse the data are. In this regard, this study uses the UK's primary data source for trip rate data (Trip Rate Information Computer System, TRICS) to understand how incomplete information can influence the types of development/policy decisions that might arise from this data. Even within this source, there are elements of missing data, and the decision of how to handle these data gaps can affect planning decisions. Based upon a trip rate regression model, a sensitivity analysis of several common methods for handling incomplete data reveals there remains substantial divergence amongst what superficially appears to be fairly robust parameter estimates and, hence, planning outcomes.