There must be an option to report traffic for a specific turn. The reason is that a given road may be moving well through an intersection, but specifically a left turn lane onto an intersecting road can be jammed. In such a case the navigator won't use that road to turn left and find another route.

As an example. Let's say I am driving on Main St and there are 3 intersecting roads coming up, Street 1, Street 2, and Street 3. My destination is at Street 2, where I need to turn left from Main St. Waze doesn't know that the left turn from Main St to Street 2 is always jammed, because of bad streetlight timing or another reason, and it will direct me to turn left as Main St in general is moving great. If Waze knew that the left turn is at a standstill then it would have directed me to turn on Street 2 right and make a U-turn, or go further on Main St and make a U-turn, or any other way to get to the destination. If no alternative then of course choose the left turn.

This ability to report traffic for specific turn should also work for right turns.