Maryland DOT defines a TOD as a place of relatively higher density that includes a mixture of residential, employment, shopping, and civil uses and types located within an easy walk of a bus (?Bus-Based TOD?) or a rail transit center (?Rail-Based TOD?). There are two primary types of bus service that impact the urban form of TODs: 1) express buses operating on dedicated rights-of-way, or along HOV lanes on major highways and freeways work in a similar fashion to commuter rail; 2) local shuttle or feeder bus services. Bus rapid transit systems may provide efficient transportation, but they do not perform well as catalysts for economic development since bus routes are not 128 permanent, real estate developers prefer fixed rail?s permanence. Busy local bus routes often are candidates for the application of TOD principles because their routes follow mature corridors that already possess many of the desired characteristics. There are some successful examples of a bus-based TOD. Cities like Ottawa, Canada and Curitiba, Brazil show that bus-based TODs can be as successful as rail-based TODs as long as they are accompanied by foresighted, intelligent planning. Case/Example: Ottawa, Canada and Curitiba, Brazil. Source/Reference: Maryland DOT, 2000, pp. 4-7; Cervero, 2000, pp. 9-10; ARC, A.