The FIA has confirmed a number of changes to track limits were made at the Circuit of the Americas ahead of Sprint Saturday at the United States Grand Prix.
Track limits were again a talking point in qualifying as drivers drifted wide at numerous corners in Austin, with Red Bull's Max Verstappen losing a time good enough for pole for straying across the boundary at Turn 19 and will instead line up sixth on the grid.
But when cars took to the track for Sprint Shootout, the white lines at Turns 9, 12 and 19 were noticeably wider.
No prior indication had been given that changes had been made, but communication mid-session revealed that the tweaks were initiated 'following discussion with the teams and drivers'.
Ironically, had the white lines been widened before qualifying on Friday, Verstappen would have kept his effort and line up on pole for the Grand Prix.
The remedy mirrors that of the one put in place at the Qatar Grand Prix, where drivers harboured similar concerns over the difficulty of keeping cars within the track boundaries.