“The intersection has been operating beyond its capacity with an increase in northbound and southbound demand,” says Todd Oliver, with Whitman, Requardt and Associates in Wilmington, Delaware, an original member of the Route 40 corridor project team. “Fortunately, we have been able to keep the plan moving and identify projects when they are needed.”
“This is another great piece of the puzzle completed for the U.S. 40 program,” says Breanna Kovach, Project Manager for DelDOT. “One great thing about the U.S. 40 program was the active steering committee, which involved people from the community.”
The department has monitored traffic, safety and other aspects of travel on the corridor to determine project priorities. DelDOT also coordinated with developers, which have contributed to several improvements near their projects.
“One of the most successful aspects of the U.S. Route 40 plan is we use a triggering mechanism to determine when improvements are necessary,” Oliver says. “An interesting part is that long-term traffic growth was not as high as expected.”
That led to construction of fewer projects, allowing funds to be used for other work needed in the DelDOT Capital Transportation Program.
The team investigated a grade separation at the SR 72 intersection, but it proved not feasible, due to the impacts it would have had on the surrounding residential and commercial developments, Oliver reports.
Future intersection improvements at U.S. 40 and SR 896 and U.S. 40 and SR 70 will include grade separations.
U.S. 40 is a four-lane, divided arterial with an average daily traffic of about 29,000 vehicles. SR 72 is a two-lane arterial with an average daily traffic of about 17,000 vehicles and provides a critical north-south link in New Castle County. The department has completed annual traffic monitoring and operational analyses since 2000.
“We determined adding another northbound and southbound through lane on SR 72 would be critical to improve traffic operations,” Oliver says.
The project runs along SR 72 from south of Del Laws Road, which is being realigned, to Belltown Run, and includes widening of north- and southbound SR 72 to four lanes for about a mile. Left-turn lanes also are being added to U.S. 40, east- and westbound. The intersection project also added pedestrian sidewalks and bicycle lanes and replaced a 50-year-old corrugated metal arch culvert under SR 72. The project required additional right-of-way but had no major environmental issues. The plan used retaining walls at the south end of SR 72 to avoid existing wetlands.
Whitman, Requardt and Associates serves as the design consultant on the project and the 20-year corridor plan.
“We have been able to maintain this effort, in partnership with the department, to keep the plan moving,” Oliver says. “Seeing these projects on the ground and providing a public benefit is very important to the team.”
Work began in spring 2018 on the culvert installation, and the overall project is scheduled to be complete in late 2020.
“The project has progressed very well, and we have had a good relationship with the contractor, which did a great job on the project keeping it on schedule,” Oliver says. “The contractor hit the targets and received the incentives.”
The most challenging aspect of the project was the replacement of the metal-arch culvert with a 15-foot by 10-foot reinforced concrete box culvert, says Dan Orr, Project Manager for A-Del.
“I had some very dedicated guys who were willing to work six or seven days a week for the entire summer,” Orr says.
A-Del installed steel sheeting to keep the work area dry from the stream and set the crane close enough to install the 17 main concrete pieces and six pieces on the wing walls on the ends for the new culvert. This aspect of the project required a 10-week detour of SR 72.
“There was a lot of pressure to get that culvert done quickly and efficiently,” Oliver says. “The contractor and construction field personnel working on it kept it moving forward.”
A-Del had to install rock in the culvert to simulate a natural stream bottom condition. Crews then backfilled, graded, paved and placed the proposed guardrail.
At the second closure, A-Del drove steel sheeting into the ground for 300 feet and poured a concrete cap at the southern end of the project on SR 72.
Whitman, Requardt and Associates provided the contractor with electronic files, and A-Del used them to program the heavy equipment, using GPS for grading and paving. “It’s very helpful, quicker and less labor intensive,” Orr says.
A-Del maintained traffic through the intersection, except for the two closures. The project was sequenced, with eight phases, to accommodate vehicle and pedestrian traffic.
“Maintaining traffic at the intersection of two arterial roadways in a construction zone is a big challenge,” Oliver says.
Throughout the project, the contracting, design, and ownership team worked collaboratively, solving any issues together. A-Del also currently is working on another corridor improvement project and completed another project years ago.
“I’ve found things always go much more smoothly when you work with the owner,” Orr says. “It makes for a better project. … and this has been a good project for us.”