The population growth in and around the area has led to growing traffic. The average daily traffic count on MD 85 is 43,000 vehicles as of 2019 and is projected to reach 52,000 vehicles by 2030, while the average daily traffic count on I-270 is 90,000 vehicles as of 2019 and is projected to reach 130,000 vehicles by the 2030. Southbound traffic is congested in the morning, and northbound traffic faces similar issues in the evening.
“Transportation has been a hot topic in the area for many years due to its growth,” says Elizabeth Harris, a Community Relations Manager for MDOT SHA.
Among the project's elements is the replacement of two poorly rated bridges on I-270. The bridges were constructed in 1950, and MDOT has serviced them in the past. However, they decided to replace them to better handle the increased volume. The new bridge on I-270 over MD 85 will have four lanes in each direction, including new exit lanes and wider shoulders. Over a one-mile stretch of MD 85, the team is constructing an additional travel lane in each direction. Lastly, the project includes the construction of a new median and partial diverging diamond interchange (DDI) on MD 85 to improve traffic flow and access to and from I-270.
The interchange was the driving element of the project. “The previous interchange and signals were starting to fail due to traffic volumes,” says Bruce Cain, an Assistant District Engineer for MDOT’s District 7 Construction, “so we decided to upgrade the interchange and bridge as it was becoming structurally deficient.”
Pedestrians will also benefit from the project. The team is installing a new sidewalk, pedestrian signals, and bike lanes.
Cain adds, “MDOT SHA’s policy is to minimize traffic issues and maintain as many lanes as possible during construction, so we have to build in smaller pieces to keep traffic moving and continue the existing pattern.”
Communicating with the driving public and the community about traffic shifts is done via social media, newsletters, radio stations, websites, and local municipal websites. Once the shift is within seven days, it is communicated on electric message boards along the roads.
There’s a substantial amount of limestone underground in Frederick County. When this is the case, sinkholes are common. Therefore, sinkhole mitigation is a significant element of the project.
To try and prevent future sinkholes, the team identifies grout areas. Before construction, nine grout areas were identified by the geology team and a tenth was added during construction, according to Mark Allen the MDOT SHA District 7 Project Engineer, who runs the day-to-day operations on the project.
These areas are considered potentially dangerous, and the aim is to prevent sinkholes from occurring there. In these areas, the rock is not flat, but instead, it is like fingers and sinkholes form as groundwater seeps beneath the surface and fills in the voids. This can cause the road to cave in.
The team drills holes in the trouble spots and pumps grout in at low pressure to fill in the voids and prevent future sinkholes.
There have been times during the project that Fay has had four different subcontractors working, as well as 30 to 40 of their own people working simultaneously. “Making that many parts work well takes organization, which is required for a complex project like this one,” Clingan says.
Cain notes that Fay looks at means and methods and presents alternative ideas to increase productivity. He cites an example, “We’ve run into some issues with unknown utilities, and the contractor has partnered with us to find workarounds, including rearranging phases to mitigate delays and avoid others.”
The total project cost is $87.7 million, of which $66 million are construction costs. The project is being funded by the traditional 80/20 split, with the federal government paying the larger percentage and the state government paying the lower percentage. Frederick County is contributing a small amount to upgrade water lines. They decided to upgrade the waterline simultaneously as the team would already be on site.
Since construction began in fall 2017, the project has gone over budget due to delays related to the utilities and design plan revisions. Cain is hopeful there will be some underrun to enable the team to be under the revised budget. The main source of hope comes from an adjustment to a stormwater management system.
The project was originally scheduled to be complete in 2021. However, due to the issues that impacted the budget as well as COVID-19, the new expected completion date is spring of 2023.
When the project is finished, the area will have increased capacity and enhanced safety. “The partial DDI is a significant upgrade to the old interchange, and will allow traffic flow faster and more smoothly,” Clingan says. “The dedicated merging lanes will reduce accidents at the interchange.”