Wheelchair ramps at street intersections are a simple product of construction. In California, the standards for these ramps are established by the State Architect and are common to all agencies that own public streets and build pedestrian facilities in the state. There are 541 such street-owning agencies. When 541 agencies produce a simple product to the same requirements, one might expect to find little difference in the cost of the product or the time taken to produce it. This proved not to be the case. A significant pattern of difference was found between the cost and time to produce ramps by the State Department of Transportation (DOT) as opposed to the cost and time to produce ramps by local cities. The differences appear to be rooted in historic practices which, in turn, are rooted in the procurement laws that govern to two types of agency. Those laws date back to 1875 and 1883 respectively, and they have led to the DOT adopting a more product-based form of specification while cities use specifications that emphasize performance. This difference in specifications drives the cost and schedule differences. The paper illustrates the use of benchmarking between agencies and the “path dependent” influence of historic practices.
Theory, flow, set based design (SBD), product design, performance based design, transportation, wheelchair ramps
Blampied, N. & Tommelein, I. D. 2016. Product Versus Performance Specification for Wheelchair Ramp Construction, 24th Annual Conference of the International Group for Lean Construction , -. doi.org/ a >
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