Volkswagen operated a top-secret site at its sprawling headquarters to test the diesel technology at the heart of the emissions-cheating scandal, reflecting the lengths those involved went to conceal their actions, people familiar with the matter said.
Some engineers used the research facility in Wolfsburg, Germany, to upload the software that manipulated regulatory emissions checks, one of the people said.
The test stand, just a stone's throw away from the main office tower where top executives sit, had unusually tight security rules that prevented access to those not involved in the project, including high-level employees who could enter all other development sites, another person said. The people spoke on condition of anonymity.
Volkswagen declined to comment on internal facilities and findings into investigations into the roots of the manipulations.
While Volkswagen has said the manipulation was restricted to a small group of rogue engineers, the existence of a dedicated test site, which hasn't been previously reported, shows that that work occurred in close proximity to the offices of top executives and raises fresh questions about what management knew about the illicit conduct.