A few days ago, I listened to a group of environmentalists on the evening news protesting a plan to build a new bridge that would solve traffic congestion and make it easier for people get in and out of a local large city. The protestors wanted the money spent instead on public transit, claiming that this options had not even been examined, and arguing that their solution would solve the transportation problem without requiring construction of new infrastructure.
I looked more closely at both alternatives. The government and the consultants retained to propose solutions to the problem had advanced several standard options, all of which revolved around either a bridge or a tunnel, while the environmentalists had extended the options by one – adding public transit as a means to achieve a similar result.
This seemed logical until I started thinking about the need to add one other criteria to the equation: the need to reduce carbon emissions.