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 Olympic Games scheduled to take place in Barcelona the next year, where the circuit acted as the start and finish line for the road team time trial cycling event. The Circuit de Barcelona-Catalunya should not be confused with the Montjuïc circuit, which hosted the Spanish Grand Prix four times between 1969 and 1975 and, unlike the Circuit de Barcelona-Catalunya, is actually located within the city of Barcelona. Because so much testing is done at this circuit, Formula One drivers and mechanics are extremely familiar with it. This has led to criticism that drivers and mechanics are too familiar with Catalunya,