Susumu Miura, a Nissan Research Center manager, shows off a Nissan car that is coated with special “cool paint” at Tokyo’s Haneda Airport on Tuesday. Yuri Kageyama/Associated Press

TOKYO — Nissan showed Tuesday what it called a “cool paint” to keep people inside vehicles cooler, although the coating is six times thicker, making commercialization still a challenge.

The company’s announcement Tuesday was timely, coming as Japan was enduring sweltering, record-high temperatures.

Nissan tested the paint on vehicles scuttling around Tokyo’s Haneda Airport, where there are plenty of unshaded areas that make it a good place to assess such technology.

The vehicles with the special paint looked like ordinary cars but felt much cooler to the touch.

The cool paint lowered the cars’ roof-panel temperature by 22 degrees Fahrenheit and the interiors by 9 degrees, according to Nissan.

Cooling materials already are widely used in buildings and other items. Cooler cars can reduce use of air conditioning and relieve the toll from heat on engines or electric vehicle batteries.

Toyota has also been experimenting with paint that delivers lower cabin temperatures, mostly focusing on colors that refract the sun’s rays.

Nissan’s cool paint reflects sunlight better and also creates electromagnetic waves that block the rays, redirecting energy away from vehicles.

Nissan’s paint was developed with Radi-Cool of China, which developed a film, fabric and coating that cut heat. Radi-Cool works with various other Japanese companies, offering cooler-feeling hats and sun parasols. Nissan is the only Japanese automaker partnering with Radi-Cool.

Susumu Miura, a Nissan Research Center manager, said there were no discernable negative effects to people’s health from the electromagnetic waves emitted by the paint. Such waves are all around us, he said.

“My dream is to create coolers cars without consuming energy,” he said.