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
Marina Bay Street Circuit Circuit ahead of 2015 Singapore Grand Prix. The modifications run from Turn 11 to Turn 13; drivers will still turn right at Turn 11 but it will now kink left slightly on entry, with the track shifting to the left-hand side of Fullerton Road. This will change the profile of Turn 12, as drivers will now use the other side of the Anderson Bridge, while the hairpin at Turn 13 has been widened by a metre in order to increase overtaking opportunities. Marina Bay Street Circuit starts with a specially made pit straight with the first DRS zone. The pit