When is it legal to cross solid lines?

In Alberta, solid lines are used to indicate that crossing them is prohibited for safety reasons. This is established to maintain orderly traffic flow and to help prevent collisions, particularly in areas where visibility is poor or where there are frequent turns, merging traffic, or pedestrians.

The regulation is clear: solid lines indicate that drivers should not change lanes or cross into oncoming traffic, except under specific circumstances which do not include the options presented. Therefore, the correct understanding is that it is never legal to cross solid lines, as doing so can lead to dangerous situations for you and other road users.

When considering the other choices, it's important to note that while turns signal a change in direction, they are typically indicated by different line markings on the roadway, such as broken lines. Emergencies that might necessitate crossing lines usually do not justify such actions, as safe driving practices dictate that one must always adhere to lane markings.