Facilities and roadways built specifically for use by express bus and high occupancy vehicles require substantial, often massive infrastructures to support what tend to be the largest vehicles operating on city and suburban streets. Separated and elevated bus way structures resemble elevated reinforced concrete freeway designs; while the roadbed and pavement requirements of bus lanes should lead planners and operators of express bus services to exercise cautionary diligence in evaluating the capacity of existing streets to withstand the additional loads and stresses imposed upon them by vehicles larger and heavier than anticipated in the streets’ engineering design.
A localized example of this additional strength requirement for bus service is demonstrated at a simple curbside bus stop. Experience has demonstrated that asphalt roadways cannot handle the stress of the braking maneuvers by the heavy vehicles. The braking action causes the roadway material to “flow” into pressure waves and eventually break into pieces, creating potholes and automobile suspension hazards. Most government agencies operating frequent bus service find it necessary to construct high strength concrete stopping areas at each location. Construction of upgraded and reinforced portions of existing streets must be systematically planned and completed in timely programs to avoid a continuous cycle of patching and repairing pavement and roadbed which generally results from the overloading caused by oversized bus vehicles.
Other construction associated with express bus services may include park and ride lots or structures, and platforms or other structures connecting bus terminals to other transportation facilities. Construction of an exclusive express bus route separately from the existing streets normally exceeds the cost of constructing a new street. The cost of building an elevated bus route is comparable to the cost of an elevated steel rail route, in terms of the size, mass and structural requirements of supporting vehicles of roughly the same size and weight. The costs of constructing elevated bus ways, railways and roadways are exceeded only by the cost of excavating and building a new subway system.
Express buses and their exclusive lanes cannot accommodate alternative use of their rights of way such as bicycle paths, parkland or other surface uses. A bicycle lane along the Orange Line Express Bus system in the San Fernando Valley of Los Angeles required additional right of way for construction of a separate bike lane. Heavy structures required for support of elevated express bus systems preclude practical use of the space beneath the bus lanes, and is unlikely to support landscaping or other uses dependent on natural light and air. Vacant spaces below elevated bus way structures may require security fencing to prevent illegal dumping and other unwanted conditions to develop below the concrete structures.
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