Good Practice Localized Bottleneck Reduction - Maryland

The Maryland State Highway Administration (MSHA) has an annual budget of $5 million to $7 million targeted toward congested intersection improvements. While this is not specifically a "bottleneck" program it nevertheless addresses congested locations that have a significant impact on the network. The program started in the Washington suburbs, when MSHA was asked to look at alternatives to building the proposed "InterCounty Connector" highway. One no-build option was to upgrade an existing, but albeit disjointed, corridor of routes that pass through 15-20 (depending on the selected alternatives) intersections. Intersections had to have a Level of Service of "E" or "F" to qualify for the program. A variety of solutions were applied, including addition of both turn lanes and through lanes. In the interim until the InterCounty Connector is built, it was deemed practical and justified to address the subject locations. The program focuses on solutions that can be achieved within the right-of-way. The program was expanded to other corridors in Maryland.

Another good example from Maryland involved a project at the I-70/I-695 (Baltimore Beltway) interchange outside of Baltimore to eliminate a long standing bottleneck problem. The eastbound approach from I-70 to I-695 backed up onto the mainline of I-70 because shortly downstream the one-lane ramp subsequently "squeezed" under a bridge superstructure. The backup onto the mainline affected mainline conditions. Widening the entire ramp would have been very expensive due to the need to widen the underpass. Instead, the ramp was widened, but only up to the bridge. This provided adequate storage off of the mainline and did so at a reasonable cost.