on origin-destination data, it models and visualises cycling levels at area, desire line, route and route network levels, for current levels of cycling, and for scenario-based ‘cycling futures’. Four scenarios are presented, including ‘Go Dutch’ and ‘Ebikes’, which explore what would happen if English people cycled as much as Dutch people and the potential impact of electric cycles on cycling uptake. The cost effectiveness of investment depends not only on the number of additional trips cycled, but on wider impacts such as health and carbon benefits. The PCT reports these at area, desire line, and route level for each scenario. The PCT is open source, facilitating the creation of additional scenarios and its deployment in new contexts. We conclude that the PCT illustrates the potential of online tools to inform transport decisions and raises the wider issue of how models should be used in transport planning. 

## 1 Introduction 

Cycling can play an important role in creating sustainable and equitable transport systems. Cycling already provides reliable, healthy, affordable, and convenient mobility to millions of people each day (Komanoff, 2004) and is one of the fastest growing modes of transport in cities such as London, New York and Barcelona (Fishman, 2016). There is mounting evidence about the external costs of car-dominated transport systems (e.g. Han and Hayashi, 2008; Shergold et al., 2012), and the benefits of cycling (De Nazelle et al., 2011; Oja et al., 2011; Tainio et al., 2016). In this context there is growing interest, and in some cases substantial investment, in cycling infrastructure, including in countries with historically low rates of cycling. 

Providing high-quality infrastructure can play a key role in promoting cycling uptake (Parkin, 2012). Off-road cycle paths, for example, have been found to be associated with an uptake of cycling for commuting (Heinen et al., 2015). Overall there is growing evidence linking cycling infrastructure to higher rates of cycling (Buehler and Dill, 2016). But where should 

