Multimodal impact fees

Impact fees have become a common funding mechanism for growth-related transportation improvements. The most common impact fee program includes a range of street and road projects, the cost of which are partially paid by new development based upon their usage of these facilities. The purpose of this paper is to describe an innovative application of impact fees to pay for transit and nonmotorized improvements in Portland OR. The City of Portland initiated a study (Henderson, Young & Company, 1997) of System Development Charges, or SDC's to help pay for growth impacts on a variety of multimodal facilities. The city is largely built-out with respect to roads, but has an aggressive program to improve transit and nonmotorized facilities. The City and a consultant team developed several innovative methods to attribute the impacts of growth to projects such as corridor-level transit facilities, sidewalks, bike lanes, and a downtown streetcar system. Special steps were needed to convert the traditional ITE vehicle trip generation rates into comparable rates for the transit and nonmotorized modes. The paper details the methodology, analysis techniques, and assumptions required. In addition, the paper describes the steps used to gain acceptance of the controversial impact fee program by a diverse group of citizens and business interests.