Its guardrails, Lexus says, are three times as strong as those on a normal test course.
"It is an especially difficult course, both on cars and people," says Shuichi Ozaki, one of two "Takumi" expert drivers who push Lexus cars to their limits here to hone their driving feel.
Toyota has invested $2.22 billion in the entire Shimoyama complex.
Aside from the Lexus campus and Mini-Nürburgring, there will be 11 other test courses for Toyota engineers to work with. On tap are a giant high-speed oval, low-friction road, dynamic pad, multi-surface drive, handling track, hill climb and load-force strip, just to name a few.
When the whole facility goes fully operational in the fiscal year ending March 2024, some 3,300 people will be working there, including those at the Lexus campus.
The Shimoyama Technical Center will become Toyota Motor Corp.'s epicenter of all future product development. It will largely supersede the company's Higashi Fuji Technical Center near Mount Fuji, which has been in use since the 1960s and is only a third of its size.
Even as rivals Mercedes-Benz, Audi, BMW and Genesis — not to mention Tesla — flood the market with battery-electric models, Lexus has yet to launch its first dedicated EV. That first vehicle, the Lexus RZ, will arrive toward the end of 2022. Lexus is tight-lipped about timelines for other EVs it has teased, including a super sleek BEV Sport performance car, a large SUV and a sedan.
Building an EV identity around driving dynamics could prove risky for Lexus.
Today's EV adopters seem more enamored with digital gadgetry such as big touch screens, connectivity and automated driving than such old school mechanics as cornering rigidity, roll angle and steering input. Lexus has historically lagged its German rivals in those characteristics.
And while the Japanese brand has long prided itself on bulletproof quality and reliability, Tesla has shown that electric car fans are happy to overlook lackluster quality for cool cachet.
Another hanging question is how Lexus will sell its handling and dynamics in a future when cars drive themselves.
"It's not a top EV brand at peer level yet," said Takaki Nakanishi, head auto analyst at Nakanishi Research Institute in Tokyo. Lexus' traditional brand promise, he said, is trust, reliability and safety.
"That is what has been demanded by loyal Lexus drivers," Nakanishi said. "Lexus has a chance now to create a new 'Lexus-ness' in moving into electrification."