Social Norms as a Cost-Effective Measure of Managing Transport Demand: Evidence from an Experiment on the London Underground

In an effort to cope with increasing passenger demand on its network, Transport for London (TfL) implemented in the second half of 2017 an experiment on one of its busiest metro train platforms. The platform surface was painted to highlight the exact location of the train doors once it comes to a full stop and to direct passengers to wait in parts of the platform that would not obstruct passengers from alighting from the train and leaving the platform. We estimate the effect of this intervention to change passenger behaviour on the platform on train waiting and delay times. We use different sets of assumptions about what the counterfactual change in waiting and delay times would have been in the absence of the intervention. Depending on the assumptions, we find that the intervention has reduced train waiting times between 0 and 6.6%. We also find that this reduction came about mainly through reducing delay times of trains once they are delayed which were cut by between 4.6% and 12.6%. The reductions are not evenly distributed throughout the day, but tend to occur during peak traffic hours. The value of the implied time savings per year are £156,000 at a cost of £25,000, amounting to a return of £6 per £1 investment. If the dwell time reduction could increase train frequency on the affected line by 1 train per hour, however, then TfL could save another £3.6 million.