A Transportation Impact Study (TIS) is conducted to evaluate the impacts of proposed developments on an existing transportation roadway system and to assist both public and private planners in making decisions with regard to the allowance or disallowance of these proposed developments.  These studies evaluate the changes in traffic attributable to the proposed development and translate them into transportation impacts in the vicinity of the proposed development.  Most studies define the on-site and off-site transportation system improvements needed to accommodate the additional traffic generated by the development. These recommended transportation improvements are termed mitigation measures.