Certain Metallic Finishes May Interfere with ADAS Radar Systems, PPG Expert Says

Nick Tullett
PPG’s Global Products and Segments Director Nick Tullett has been working with carmakers to develop refinishing products that won’t interfere with ADAS.

A decade ago, ADAS was an acronym very few people in the collision repair industry were familiar with. But now every collision repair professional on the planet knows what it means and how it affects them every day.

More and more auto body shops are taking their diagnostics in-house and hiring techs who have the proper training to do the job right. If ADAS does not work correctly or one of the systems is misaligned, people’s lives could be in jeopardy.

Within the last two years, paint manufacturers have discovered certain metallic finishes interact with the electromagnetic radiation used by radar. It may interfere with radar transmission and if it goes above a threshold set by the vehicle, it can potentially present a serious safety issue.

Paint and coatings suppliers such as PPG have evaluated swapping the aluminum pigments in the metallic finish with alternatives to significantly enhance radar transmission. These reformulated colors will maintain a good match to the car’s original finish while reducing the radar transmission loss, so safety systems can function as designed.

PPG’s Global Products and Segments Director Nick Tullett has been working with carmakers to develop refinishing products that won’t interfere with ADAS. One of his top deliverables is to help the OEs to fully understand the impact of certain metallic finishes on ADAS.

Even a low-speed fender bender can damage these advanced systems, reducing driver safety---a concern for every stakeholder involved.

“ADAS technology is actually located in areas of the car that are easily and frequently damaged,” Tullett said. “Carmakers have been installing ADAS such as forward collision, automatic emergency braking, lane departure warnings and adaptive cruise control in peripheral, easy-to-damage vehicle parts like windshields and bumpers. These parts often house radar, a system that uses radio waves to detect people, autos and other objects close to it, to enable many of these safety features. “ADAS is presenting new challenges for collision centers and for the repair industry in general,” Tullett said. “There are so many stakeholders involved, from the vehicle makers to the collision repair shops to the paint companies. Our main concern at PPG is how do we repaint and repair certain metallic colors without impeding their performance? We believe there's not yet enough leadership and direction out there to navigate through this, so our goal is to help all of the different stakeholders to make the right choices when it comes to ADAS.

"We have some numbers that indicate that about 50% of all new cars were equipped with at least one radar system and by 2025 we're expecting it to be more like 85%. So, being able to effectively repair these cars is really important for our collision center customers.”

One of the main challenges associated with ADAS is the fact many of these safety systems can be hard to detect visually.

“Collision repair shops now rely on customer discussions, visual indicators and automaker data to pinpoint ADAS,” he said. “Training to spot these various systems more precisely may be necessary for techs to determine the repair process more carefully. For example, body shops could simply repair minor bumper damage by filling scratches and then spot painting before the advent of ADAS. However, body filler compounds and new paint can impair today's vehicle sensors.

"In addition to considering the ADAS automobile’s technical safety and functionality components, techs will need education on how certain colors and particular finishes can impact the sensors of these safety components.”

Acquiring the right devices to perform repairs and calibrations is key, but training is also a big piece of the picture.

“Techs will also need training on recalibrating sensors using specific equipment and software for diagnostics, services, replacements and repairs to meet automaker specifications," Tullett said. "However, it may be some time before most shops are equipped to offer in-house calibrations because most independent collision centers don’t have the proper calibration equipment in-house. Right now, many body shops use outside diagnostic companies or take the vehicles to their local dealerships, but soon that may become impractical with ADAS in literally every new car built.”

Shops will also have to consider investing in more sophisticated estimation tools, along with technician training, in order to assess the costs of damage to driver safety technology installed in areas such as bumpers. Using historical data, predictive analytics and VIN integration, the estimation software can build a more accurate estimate for collision repair professionals.

“Until recently, automakers opted to replace instead of repair the damaged bumper, which proved expensive and with significant pushback from car insurance companies,” Tullett said. “As such, automakers have turned to paint and coatings suppliers to identify a better solution.

"PPG has partnered with many OEs to calculate the impact of all their colors," he said. "These include metallic finishes on repainted bumpers to better understand the transmission loss of radar signals. Data shows that while the vast majority of colors do not impact the functionality of ADAS, a handful of metallic finishes do pose an issue. At certain concentrations, the aluminum pigments used in metallic paints reduced the transmission of radar signals and interfered with the operation of the ADAS.

“It's a concern for paint companies because one fourth of all new cars produced every year are painted with metallic colors,” Tullett said. “It’s a very popular color space, and we don't think that car makers are going to abandon that color space. They’re looking for us to come up with solutions so that they can maintain that color space.

"We've identified a number of existing materials that we can use, so that they won’t impede with radar performance, and still give us a good color match," he said. "In the paint business, color accuracy is everything. Everybody wants their car back looking like it was never in an accident, right? The most visual thing they see is the color. So, we've identified alternative materials, and some of them are already present in our paint systems. We've identified that small number of colors which are affected and developed alternatives.”

Collision repairers will need to consider the repair guidelines and technical and service bulletins provided by automakers to keep safety intact. PPG plans to issue a technical bulletin relating to radar and the impact of certain metallic finishes for collision repair professionals.

In addition, the company recently launched the PPG KNOWLEDGE COLLEGE™ online learning management system that provides the refinish industry with the most comprehensive online training programs available.

Over the last couple of years, PPG has done a lot of joint work with carmakers, looking at their color palettes and measuring the radar transmission of the colors in their color ranges.

“We have identified any potential problem colors where the interference in the radar with the radar signal is enough to actually impair the correct functioning of the radar,” Tullett said. “It's worth pointing out that the very vast majority of colors in your own cars today are absolutely fine. They don't interfere with the radar transmission, and they won't affect the safe working of the ADAS.

“Now one of the ways that carmakers have dealt with this up until now is to make a blanket recommendation that says, when you have a car that's equipped with radar if the bumper is damaged, you may not repair that, you must simply replace it,” he said. “And by doing that what they're saying is when you replace it, it's going to have one layer of paint applied to it. And they're OK with that. What they're concerned about is if you have a repair using body filler, multiple layers of paint might interact with a radar to an extent where the performance of the radar is degraded.”

PPG is currently researching and developing a wide range of novel materials to devise solutions that won’t compromise radar in some vehicles.

“We want to retain our capability to stay within that coveted silver metallic color space that is much more transparent to radar than aluminum or other existing pigments,” Tullett said.

As ADAS evolves, companies such as PPG will be working hard to develop products that will complement rather than impede ADAS, especially radar.

Ed Attanasio

Ed Attanasio is an automotive journalist and Autobody News columnist based in San Francisco.

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