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GDOT - I-20 at Washington Road Lighting

Perfect Timing

Golf balls, birds and airplanes have a lot in common in Augusta, Georgia. All three take flight at regular intervals, and all three played a role in the timing and precision of a crucial bridge and underpass lighting project at Augusta’s I-20 and State Route 8/Washington Road interchange.

As the primary access point to Augusta National Golf Club, which draws thousands of fans to the Masters Golf Tournament each year, the busy interchange is located beside a migratory bird habitat, and is close to Augusta Regional Airport. The Georgia Department of Transportation (GDOT) determined that daytime and nighttime visibility were insufficient inside and above the 80-foot-long underbridge at the intersection—posing a safety hazard for motorists and pedestrians—and that time was of the essence to design and build a cost-effective lighting solution without disrupting nature, sport or aviation.

Though far from GS&P’s first project for GDOT, the groundbreaking opportunity represented a new frontier as the state’s first design-build lighting project.

“We were just really aggressive with our design,” says Carla Holmes, senior transportation engineer. “We had clear milestones, and we coordinated closely with GDOT, the contractor and the vendors.

“It meant a lot to us that GDOT trusted GS&P enough from our previous work to allow us to assist them with the first lighting design-build project. To partner with them in developing the policies for this process was an exciting challenge for our team.”

Stepping Back to Step Forward

At the project’s critical starting point, GS&P and electrical contractor Brooks Berry Haynie & Associates resisted the status quo, designing a solution that increased safety while being cognizant of the need to safeguard public funds.

“In similar projects involving long underpasses, the tendency has been to overdesign and overbuild using standard tunnel lighting that may be too bright at night,” Holmes explains. “As a result, up to 75 percent of tunnel luminaries are sometimes disconnected after construction to save on annual utility costs—meaning taxpayer dollars are wasted installing fixtures that go unused.”

The interchange’s preliminary lighting plans repeated the concepts seen in other long underpass designs.  Instead of relying on routine design practices, the design-build team recognized an opportunity to provide a solution that can both meet the needs of the I-20/Washington Road  underpass, and be replicated to address similar situations on other projects.

“We approached GDOT with the idea of modifying the underpass lighting design to avoid over-shooting the lighting and ending up with astronomical lighting costs not only up front, but for many years to come,” Holmes says. “Previous designs may have just taken the standard specs and put the tunnel lighting in, but we wanted to make sure the state–and ultimately Georgia taxpayers–didn’t waste money they didn’t need to spend.”

GDOT officials agreed, and gave GS&P the go-ahead to work up a more efficient plan.

“We tried a number of different options and arrived at a hybrid lighting design that used fewer fixtures but still exceeded the goals of providing greater visibility and safety,” Holmes says.

The team conducted studies to demonstrate that the updated design met the required amount of luminescence both during the day and at night, and team members used 3-D models and light-visualization software to reduce the number of lighting fixtures needed in the underpass. As a result, installation costs were reduced, and the innovative design saves more than 40 percent annually on operation and maintenance.

Designing both a cost-effective and safe solution was “very gratifying,” says Holmes. “You’re not often able to affect the outcome as much as we were here—especially with something new.
"We understand from our work on all types of roadway projects that dollars do matter. You have to meet safety standards, but in a lot of cases there is flexibility. Anything we can do to optimize safety and save taxpayer dollars is a good thing.”

The View from Behind the Wheel

Underpasses longer than 80 feet can create circumstances similar to a tunnel and, as such, carry recommendations for supplemental daylighting from the American National Standards Institute, as well as the Illuminating Engineering Society.

To meet the standards, GS&P designer Jason Boyll emphasized the importance of rethinking the interchange’s lighting through the eyes of a motorist approaching the underbridge.

“On a sunny day, a driver’s eyes must adjust quickly to lower light levels. If the inside of the underpass is too dim, the driver’s ability to distinguish between objects and perceive potential obstacles is diminished,” says Boyll. “It may look like a ‘black hole’ if proper daytime lighting isn’t in place.”
Once the driver has entered the underpass and adjusted to lower light levels, less lighting is needed to maintain visibility.

“This transition lighting is designed to ease the burden on the driver’s eyes as they transition between areas of light and darkness,” Boyll continues. “Softer lighting is necessary at night, so control strategies are required to turn off the additional lighting after dark to save energy.”

“Complexities related to lighting might surprise drivers who rarely think about roadway illumination,” says Holmes. “People tend to not think much about lighting until they realize it’s insufficient. They may think it’s only a matter of putting up some light poles and flipping a switch­—no big deal. But a lot goes into roadway lighting design: the brightness, the coverage area, the transitions and the daytime and nighttime impacts.”

First Things First

Considering the delicate nature of the project, success hinged on a clear plan with detailed milestones and persistent follow-up throughout the process.

“Because the underbridge lighting was the challenging part—where we had to redesign, conduct a study and explain the approach—it took extra time that was not in the original scope,” says Holmes.

“We knew that taking those steps would compress the time frame, but it was very important that we did it right. It took a lot of coordination between the design-build team and GDOT not to jeopardize the schedule.”

As the work unfolded, GS&P’s design team kept in close contact with GDOT, the contractor, vendors, local engineers and utilities, and even Federal Aviation Administration (FAA) officials.

“Our many coordination activities included some with FAA representatives because of the interchange’s proximity to a nearby airport, and the flight path of planes taking off and landing,” Holmes says. “We kept everyone informed, and when we identified anything that might be an issue—such as the need to redesign the underbridge lighting—we raised it as soon as possible.”

And since this was the state’s first design-build lighting project, many of the necessary steps were new.

“Most of the previous design-build projects were big roadway projects, so the same processes didn’t always apply here,” explains Holmes. “We were helping GDOT retool the policy and requirements as we went along, because we knew there was value not only for this project, but perhaps even more value for future design-build lighting efforts.

“What’s great about this project is our design didn’t simply follow the textbook approach. Our team clearly identified the problem, re-imagined the best way to address it, and demonstrated care and concern for both the taxpayers’ money and for GDOT’s goals. I like that about our team. We went the extra mile.”


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Project Info

  • Client: Georgia Department of Transportation
  • Location: Augusta, GA, USA
  • Market: Transportation
  • Services: Engineering
  • Team:
    • Marion Waters, III, P.E., PTOE Principal-in-charge
    • Carla Holmes, P.E., PTOE Project Manager
    • Josh Williams, P.E., PTOE Project Professional
    • Jason Boyll Project Designer
    • Mark H. Washing, P.E.
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