In the State of Washington, drivers are required to yield to merging transit vehicles: RCW 46.61.220
...however, as you've probably noticed, this generally isn't respected or enforced. Because of this, transit agencies have specifically designed bus stops so that buses load passengers while sitting in the traffic lane, especially on arterials with heavy traffic. However, this causes yet more congestion in already congested corridors.
How do we begin enforcing the 'yield-to-transit' law? This could be done through spot enforcement, but that is expensive and inconsistent. Alternatively, traffic safety enforcement cameras* installed on buses would provide cheap and consistent enforcement of this rule, while enabling our traffic engineers to design corridors which are more appropriate for all users.
So, how will we convince non-riders that this is a good idea? This affects the time and safety of all roadway users. Designing stops to block traffic does not help us move people and goods in an expedient manner, causes dangerous weaving between lanes, and necessitates overbuilt corridors such as Rainier Avenue South. As a result, roads are more dangerous for all users.
In order to pave the way for this enforcement, the RCW pertaining to traffic safety enforcement cameras would need to be adjusted: RCW 46.63.170
Background: In order to improve bicycle and pedestrian safety on Rainier Avenue South (from South Alaska Street to South Henderson Street), Seattle Department of Transportation proposed and studied a "road diet", reducing from two traffic lanes each direction to one each direction with center turn lane and bike lanes. However, this change was deemed inappropriate because of the resulting increase in travel times for all vehicles in the corridor. This was exacerbated by buses blocking the flow of the single traffic lane, especially due to high levels of traffic and frequent transit boardings.