Many commuters who live within three miles of Hartley station drive there and pay to park, even though cycling would take them no longer. In a survey, most of these drivers said they would cycle if they could be confident that their bicycle would still be there in the evening. The disused ticket office beside the platforms could be turned into a staffed bicycle store at modest cost, and it is in full view of the station entrance throughout the day. Converting the ticket office would therefore reduce the number of commuters who drive to the station, and the council should approve the conversion.
Which one of the following is an underlying assumption of the argument?