In January 2016, 35,000 km of high-speed lines were planned worldwide for completion by 2050. Governments have sometimes to choose between different projects. If cost-benefit analysis is the most widely used tool to evaluate the effects of different projects, it seems to be inappropriate for evaluating the wider effects. Using service innovation theories, this paper shows that these wider effects in cities are difficult to evaluate ex ante because they are coproduced in space and time.