Box 5-5

USING CASE STUDIES AND META-ANALYSIS TO INFORM THE PUBLIC AND DECISION MAKERS

The California Department of Transportation (Caltrans) was planning a number of new highway bypasses to relieve congestion in local communities. However, agency planners understood that these types of projects are often controversial, with some civic leaders supporting them and local business leaders expressing concern about loss of sales. In the past, a lack of information often had led to un realistic fears and expectations. To address this problem, Caltrans staff sponsored a study to improve basic knowledge about the impacts of bypasses on the economic health of small towns. The study compiled state and national information covering more than 200 built bypass projects to assess actual before-and-after experiences and factors affecting those outcomes. The project team then developed a spreadsheet tool—the Highway Bypass Impact model—that applies this information to help forecast potential economic impacts of planned future bypasses. Caltrans staff will be using the study findings and analysis tool to enhance the ability of local residents and officials to make judgments about likely impacts of proposed projects on their communities.


SOURCE: System Metrics Group et al. 2006.

example, TRB has a Committee on Transportation and Economic Development. The National Association of Regional Councils is also active in this area, and there are associations explicitly devoted to economic development professionals. Most states and cities have an economic development group, but they do not necessarily communicate regularly with transportation planners and engineers. There is fertile ground here for communication and outreach. Implementation mechanisms may emerge from the case study research since it will involve 50 or more cases. TRB’s Committee on Transportation and Economic Development, in conjunction with FHWA and others, sponsors a major research conference every few years. One of these conferences may be an appropriate opportunity to showcase the results of SHRP 2 work in this area.

The greatest barrier to implementing products of research in this theme area is the inherent complexity of the topic and the lack of transparency of traditional tools. The data-based, econometric approach yields answers,



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