When assessed according to its degree of democratic achievement (from mere information through consultation to genuine negotiation), public debating in local policy making is criticized for its ambiguity. Local government officials deplore its deadlocking effects while citizen/users denounce it as all pretence. Moving beyond such arguments about whom public debate is beneficial to, this research on the making of local transport plans in France has sought to identify what public debate actually produces. Two main results were obtained. The first one is that public debate is more productive (i.e. has more impact on the content of the plan) when it occurs early in the process. The second result is that a "targeted" form of public debate (when local authorities select the organizations that will be involved in the debate) brings counterweight to technical-political arguments, while a "revealed" form of public debate (when unexpected or uninvited participants get involved in the debate) introduces new themes in the project.
