Circuit de Monaco downhill again to a double right-hander called "Portier," named after region of Monaco, before heading into the famous tunnel, a unique feature of a Formula One circuit. (Until 2009 only one other circuit, Detroit in 1982–88, featured a tunnel, but the F1 series now includes racing at the Yas Marina Circuit in Abu Dhabi, which presents a shorter tunnel at the exit of the pit lane.) As well as the change of light making visibility poor, a car can lose 20–30% of its downforce due to the unique aerodynamic properties of the tunnel. The tunnel also presents a unique problem
Circuit de Barcelona-Catalunya Prix from 1992 and later the Catalan motorcycle Grand Prix since 1996. There are at least five points on the track (turns 1, 2, 4, 10, 14) where riders are known to overtake. As in Formula 1, Turn 1 is arguably the most popular place for overtaking. The circuit is not known to produce copious amounts of overtaking, despite the long straights. Originally, the Formula 1 circuit changes were not instituted for MotoGP; however, after a fatal crash in the 2016 MotoGP round involving a Moto2 rider, the Formula 1 layout was implemented to slow down riders for safety purposes.