About Turning left: the wide arc, and three exceptions to 'left-past-left': which statement is correct?
When turning left you only need to look ahead (oncoming traffic and the turn); traffic coming up behind you is no longer relevant once you are turning.
'left-past-left' applies, UNLESS: the oncoming driver has already clearly committed to a turning position, road markings indicate otherwise, or there is a wide central reservation.
When turning left you only give way to oncoming traffic going straight; oncoming traffic that is itself turning right does not need to be given way to.
Explanation
trap: exceptions ignored. Book p.139 - 'left-past-left' applies, UNLESS: the oncoming driver has already clearly committed to a turning position, road markings indicate otherwise, or there is a wide central reservation