It could be due to its doors. Seriously.
Over the past several days there’ve been updates regarding the upcoming Bugatti Veyron successor, possibly to be called the Chiron. Development and prototype testing is currently underway. But not so long ago it was predicted the Chiron would debut sometime in 2015. That date has now been pushed back to 2016. Bugatti or anyone else from within the VW Group has yet to offer an exact explanation, but there are few clues as to why. The hypercar’s powertrain has been finalized: the continued use of the 8.0-liter quad-turbocharged W16.
At least two of those four turbochargers will be powered electronically. So what’s the reason for the holdup? The doors. Apparently, VW supremo Ferdinand Piech and VW Group chairman Martin Winterkorn, who’ve both test driven prototypes, weren’t happy with the Chiron’s door concept, which is supposedly "handicapped by excessively wide sills and a narrow opening angle." Piech offered a solution which would see "the door and the outer part of the sill swing up together." This would result in much easier entry and exit, but would also require extensive and costly reengineering. If the order has been given for that, the reason for the delay may be solved.