Laña, IbaiOlabarrieta, Ignacio (Iñaki)Vélez, ManuelDel Ser, Javier2018-05Laña , I , Olabarrieta , I , Vélez , M & Del Ser , J 2018 , ' On the imputation of missing data for road traffic forecasting: New insights and novel techniques : New insights and novel techniques ' , Transportation Research Part C: Emerging Technologies , vol. 90 , pp. 18-33 . https://doi.org/10.1016/j.trc.2018.02.0210968-090Xresearchoutputwizard: 11556/523Publisher Copyright: © 2018 Elsevier LtdVehicle flow forecasting is of crucial importance for the management of road traffic in complex urban networks, as well as a useful input for route planning algorithms. In general traffic predictive models rely on data gathered by different types of sensors placed on roads, which occasionally produce faulty readings due to several causes, such as malfunctioning hardware or transmission errors. Filling in those gaps is relevant for constructing accurate forecasting models, a task which is engaged by diverse strategies, from a simple null value imputation to complex spatio-temporal context imputation models. This work elaborates on two machine learning approaches to update missing data with no gap length restrictions: a spatial context sensing model based on the information provided by surrounding sensors, and an automated clustering analysis tool that seeks optimal pattern clusters in order to impute values. Their performance is assessed and compared to other common techniques and different missing data generation models over real data captured from the city of Madrid (Spain). The newly presented methods are found to be fairly superior when portions of missing data are large or very abundant, as occurs in most practical cases.162412545enginfo:eu-repo/semantics/restrictedAccessjournal article10.1016/j.trc.2018.02.021Traffic forecastingMissing dataCluster analysisData imputationTraffic forecastingMissing dataCluster analysisData imputationCivil and Structural EngineeringAutomotive EngineeringTransportationManagement Science and Operations ResearchProject IDinfo:eu-repo/grantAgreement/EC/H2020/691735/EU/REnaissance of Places with Innovative Citizenship and TEchnolgy/REPLICATEinfo:eu-repo/grantAgreement/EC/H2020/691735/EU/REnaissance of Places with Innovative Citizenship and TEchnolgy/REPLICATEFunding InfoThis work has been supported by the Basque Government through the ELKARTEK program (Ref. KK-2015/0000080 and the_x000D_ BID3ABI project), as well as by the H2020 programme of the European Commission (Grant No. 691735).This work has been supported by the Basque Government through the ELKARTEK program (Ref. KK-2015/0000080 and the_x000D_ BID3ABI project), as well as by the H2020 programme of the European Commission (Grant No. 691735).http://www.scopus.com/inward/record.url?scp=85043226955&partnerID=8YFLogxK