After recording a nearly 50-percent decline in traffic fatalities between 2004 and 2014, the Georgia Department of Transportation (GDOT) saw a dramatic 30-percent upswing between 2014 and 2016. This significant difference in data prompted the department to seek action to bring those numbers down, according to Andrew Heath, GDOT’s State Traffic Engineer.
When looking at the data, Heath said many of the fatalities were happening during wet conditions and nighttime. GDOT knew it needed to implement new wet-reflective pavement markings to improve visibility on the roadways.
“We decided as a department that we needed to take an all-hands approach in terms of dealing with that safety situation as it was unfolding,” Heath said. “That led us to a very strong strategy from a pavement markings perspective in deploying what we saw as the most safe products on our roadways.”
Investing in a Practical Solution
When deciding on which solutions to invest in for Georgia’s roads, Heath said it was important to consider both cost and performance to make sure the state’s taxpayers were getting the best bang for their buck. These needs ultimately led GDOT to specify Stamark 380/381 All Weather Tape from 3M for their roadways.
“The department made the decision to use 3M’s tape because it checked all those boxes—from a retroreflectivity perspective, from a longevity perspective and from a life-cycle cost perspective—that we felt confident we were being strong stewards of the taxpayers’ dollars,” Heath said.
Designed for long-term reflectivity, 3M’s all-weather tape is highly retroreflective in both dry and wet conditions. It’s comprised of abrasion-resistant microcrystalline ceramic beads that are bonded in a durable polyurethane topcoat. The tape can be used as an inlay marking on new asphalt or as an overlay marking on most asphalt and concrete pavement surfaces.
In Georgia, the wet-reflective tape is now specified in all of GDOT’s concrete pavement projects that see high truck traffic. The tape has been regularly implemented all around the state.
Heath said the product has performed strongly since implementation, especially on the long longitudinal sections of roadway across the state, including interstates like I-16 in southern Georgia. In these areas, the department has seen a reduction in lane departure-related crashes and wet weather-related crashes.
“We’ve seen that life-cycle cost proposal that we were initially considering come to fruition, in that the product has lasted for multiple years and is continuing to perform strongly 4-5 years after it was initially installed,” Heath said.
In a study conducted by Beck Engineering in 2019, a mobile retroflectometer and rainbox were used to measure the reflectivity of the striping in simulated rainfall, in order to determine wet continuous retro data. The study showed that the markings on stretches of Georgia highway had dry retroreflectivity measurements above 1,000 and wet continuous measurements as high as 522, years after installation, numbers that far exceed the state’s specifications for brand new pavement markings, according to Heath—GDOT’s dry retroreflectivity requirement for new construction is 600 for white markings and 400 for yellow markings.
“I’m not seeing anything in those numbers to demonstrate that we need to go out and restripe that road,” Heath said. “It helps us out from a life-cycle perspective that we’re not having to go out and restripe roads in a continual manner. We can get a number of years from one application.”
The Future of Roadway Safety
Looking forward, Heath said he anticipates that changes in the ways people travel and the growth of technologies like autonomous vehicles will dramatically change the way GDOT does business. With the introduction of connected and driverless vehicles into the traffic fleet, he said it becomes even more important to have strong infrastructure in place.
“It’s going to become incumbent upon departments of transportation to ensure that there is a robust infrastructure that’s well-maintained to support the deployment of those technologies,” Heath said. “That ranges anywhere from the condition of our traffic signals to our pavement markings, to the pavement itself, to make sure that these vehicles and this technology can operate the way they’re supposed to successfully.”
Not only does keeping its roadways in good condition set the state up for success with emerging technologies, it also improves safety for human drivers already on the road. Heath said that improved retroreflectivity of pavement markings, improved pavement conditions and well-maintained signals all come with inherent safety-related benefits for the general population.
Safety is ultimately Heath’s biggest concern, and minimizing traffic-related fatalities on Georgia’s roadways is always top of mind in his role as traffic engineer.
“What keeps me up at night is figuring out how we can get from a reactive mode as a department to a proactive mode, so we can look to prevent those fatalities before they become reality,” he said.