How do pilots of big jets determine if they are clear of the runway after landing? The pilots of small aircraft can easily determine if they're clear of the runway by visually looking back through the side windows.

How do the pilots of big commercial jets determine that all parts of their aircraft are clear of the runway after landing? It looks like the same visual check as used by GA is almost impossible given the size of their aircraft. Do they have some special ways or measures to do that?
Using TLAR (That Looks About Right).  Pilot turns off a runway onto a taxiway spur and sees the runway safety area lines and just estimates a point beyond roughly equal to or greater than the length of the fuselage and places the cockpit over that point.

Other methods include geo-referenced airport diagrams on a moving map display showing the position of the aircraft.