Short-term traffic forecasting: Where we are and where we’re going

•Recent short-term traffic forecasting literature is categorized and analyzed.•Relevant work in 10 challenging, yet relatively under researched, directions is thoroughly discussed.•Suggestions for future work are provided and discussed. Since the early 1980s, short-term traffic forecasting has been an integral part of most Intelligent Transportation Systems (ITS) research and applications; most effort has gone into developing methodologies that can be used to model traffic characteristics and produce anticipated traffic conditions. Existing literature is voluminous, and has largely used single point data from motorways and has employed univariate mathematical models to predict traffic volumes or travel times. Recent developments in technology and the widespread use of powerful computers and mathematical models allow researchers an unprecedented opportunity to expand horizons and direct work in 10 challenging, yet relatively under researched, directions. It is these existing challenges that we review in this paper and offer suggestions for future work.