He could not find any space to move in front.[153] The mandatory change for drivers to switch into their second cars began on lap 18 when Engel and Piquet became the first drivers to enter the pit lane. Rosenqvist followed on the next lap with Vergne, López and both ABT Schaeffler Audi Sport cars of di Grassi and Abt staying on track for an additional lap to allow all four drivers to run in clean air.[155]