Case Study:

Montgomery County, Maryland

Methodology

Accessibility Measures

Montgomery County selected three types of accessibility measures to compare alternatives:

1. Destination accessibility, or the number of destinations that can be reached within a fixed travel time. This measure is based on the number of job opportunities that can be reached within 45 minutes by Montgomery County households, and the number of homes that can be reached within 45 minutes from major activity centers of Montgomery County employment. The method for computing these measures is described below. The measures are calculated separately using auto and transit travel times.
2. Fixed-guideway transit accessibility, measured by the percentage of businesses and residences that are located within one-half mile of fixed-guideway transit stations. The Washington region's extensive rail transit network can provide significant time and cost savings for many trips. This measure also indicates the extent to which options are available to households that either cannot afford or choose not to own a vehicle.
3. Travel times, measured by average travel times for auto and transit work trips in the evening peak hour. The county's objective is to reduce travel times, especially for transit trips.

In addition to these accessibility measures, the county also computed other measures relating to mobility and environmental impacts. These included VMT, VHT, average travel speeds, and mode shares.

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