Why is it important not to pass trolleys on a two-way street?

The importance of not passing trolleys on a two-way street stems from the fact that operators must wait for the trolley to operate over the switch. Trolleys often share their tracks with other vehicles, and they can encounter switches where they may need to change tracks. If a bus operator were to pass a trolley before it completely clears the switch, there is a risk of collision or causing the trolley to derail, which can lead to serious accidents. By waiting for the trolley to fully clear the switch and operate safely, the bus operator ensures that all vehicles on the road can navigate without risk of accidents, thus maintaining safety for all road users.

The other options may seem plausible but do not encompass the critical operational and safety issues involved in passing trolleys.