If the distance from the centre of the tractor steering wheel to the front edge of a mounted implement exceeds 3.50 metres, what safety measure is legally mandatory when entering intersections with impaired visibility?

1. The driver must sound the horn before entering and may then proceed
2. The driver must use a guide person (Einweiser) on foot, or an approved cross-traffic mirror or camera system giving a view of the crossing traffic
3. The driver must switch on the amber beacon, which then confers priority
4. The implement must be raised to its highest position so it clears the cross-traffic