Case Study:

Montgomery County, Maryland

Overview

This case study illustrates the use of accessibility measures in regional planning. The measures can be readily computed using land use and network data typically available from a regional travel demand model. The results showed clear differences in accessibility among alternatives.

Montgomery County, Maryland, northwest of Washington, D.C. (Figure 1), is the largest county in the state. To address significant transportation problems, the county has recently undertaken a number of major investment and project studies. Yet, these studies have generally been conducted in isolation - each assuming that the other projects will not occur.

Not satisfied with this piecemeal approach, the Montgomery County Planning Board recently asked planning staff to evaluate a 20-year future with different transportation projects in conjunction, and to recommend a set of near-term improvements. The board also asked staff to look at longer-term future networks, including conceptual projects such as circumferential transit. Montgomery County planning staff chose to use accessibility as one of a few key indicators of the performance of each alternative transportation scenario. The county's accessibility measures indicate how many jobs the average household can reach within a given travel time, as well as how many households can be reached in a given travel time from employment centers.

Figure 1. Montgomery County, Maryland

Fig. 1 Montgomery County, Maryland

Source: Maryland-National Capital Park & Planning Commission (1999).

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