In a multi-manning (Doppelbesatzung) long-haul operation from Vienna to Madrid, Driver A drives for 4.5 hours while Driver B sits in the passenger seat (availability). They switch, and Driver B drives for 4.5 hours while Driver A sits in the passenger seat. After taking an extension, each drives another 4.5 hours. Exactly how much maximum total driving time can the team achieve before they must stop the vehicle for their mandatory 9-hour daily rest within the 30-hour window?

1. 18 hours of driving (plus 2 hours for changeovers/other work), reaching the maximum 20 hours of daily driving permitted when both drivers utilize their 10-hour extension
2. 21 hours of driving, because multi-manning allows each driver to drive 10.5 hours per shift
3. 16 hours of driving, because driving time in multi-manning is capped at 8 hours per driver
4. 24 hours of driving, because the truck is allowed to drive continuously for the full 24-hour cycle