How the Default Unit Cost was Determined
A number of sources for bridge costs were consulted including state DOTs in Iowa, Florida, Vermont, and Wisconsin. Ultimately, the VTrans data on bridge costs were selected both because they were specific to bike/pedestrian facilities and because they included a unit cost (square feet) that could readily be applied to the model. The Vermont estimate of $100/square foot for bridge construction, also appeared to be consistent with the range of costs from the other state DOTs. It should be noted, however, that the Vermont figures were for spans of 100 feet or less.