KCI provided highway, structural, geotechnical, traffic, and water resources engineering services to upgrade an existing interstate interchange and build a new urban diamond interchange at a nearby intersection in Harford County. Capacity and safety had become major concerns at MD 24 where evening rush-hour traffic routinely slowed and backed up onto the interstate. The interchange is among the busiest north of the Baltimore Beltway and provides access to a major shopping hub as well as Aberdeen Proving Ground, which has experienced an influx of new jobs and families through the Base Realignment and Closure (BRAC) process. Less than one half mile down the road, the MD 24 intersection with MD 924 was also experiencing severe congestion and higher than normal accident rates. KCI led a team working with the Maryland Transportation Authority (MDTA) to tackle both challenges at the same time by upgrading the existing I-95 interchange at MD Route 24 and replacing the MD 24/MD 924 intersection with a full grade-separated urban diamond. Because the junctions are located so closely together, an integrated solution was required.
Our team designed improvements that would allow traffic to flow freely through the MD 24/MD 924 interchange to eliminate backups on I-95 and accommodate capacity 25 years in the future. Plans were prepared and advertised for bid, but before a contract was signed, the Authority wanted to take a second look at the proposed dual interchanges to incorporate future plans for a major widening along I-95 planned as part of the agency’s multi-year and multi-billion Express Toll Lanes initiative. MDTA wanted to minimize the amount of rework required when Section 200 moved into the construction phase. Because the project had already been bid, the Authority asked the team to complete the redesign under an accelerated schedule with a secondary goal of compressing the project’s construction time line. Design staff brainstormed short-term, flexible alternatives that were compatible with future improvements, improved operations, and maximized the existing roadway and bridge assets. Critical challenges also included minimizing congestion and reducing construction cost while still meeting the original safety and capacity objectives.
With construction complete and open to traffic, the project has met all of its goals. Even though the Section 200 project is indefinitely on hold, the KCI team’s innovative interim solution bought near-term years of service at a nearly $25 million cost savings and a significantly reduced construction time frame, but will still be compatible with future improvements when funded.