Good street design for transit requires a balance between two goals: serving dense, mixed-use places, while providing reasonable travel times and reliable operations. Busy streets—where walking and bicycling are practical and pleasant—signal vibrancy, and also tend to be important destinations for people arriving by any mode. But these popular and busy streets also often result in slow and unreliable transit.
Transit speed and travel time not only affect customer satisfaction and ridership, they also underlie operating costs. The slower and more variable transit travel times are, the more transit agencies must spend to deliver the same frequency of service. Where transit runs in mixed traffic, it is common for transit travel times to decline slowly as the city develops. Transit agencies must then pay more to maintain the same frequency of service along slower routes rather than spending those resources offering more service.
Designing streets for transit, walking, bicycling, and driving is possible, but the right answer is different in different places, and it always requires both creativity and compromise.