It's Friday night as I board a 72 local to Lake City at its first stop, International District. As we pass through the stops in the tunnel, the bus gets more and more crowded, to the point where the whole aisle is filled with people. The bus gets even more packed as we pass through Eastlake. People get off too, but it's almost impossible at this point, because people stuck in the middle of the bus have to squeeze in between everybody, which becomes extremely cumbersome. Many people miss their stops because of this.
This also predictably results in large delays. The time it takes at every stop to get off the bus is absurd, and the route is extremely slow because of that. The average speed of the bus, as calculated by Google's excellent My Tracks application, was well under fifteen miles per hour.
Imagine if there were only two doors on an average subway car, or even a Link car. The length of a Sound Transit light rail car and articulated buses in the Metro system are comparable, although Link cars are longer. The time the train would take at each stop would be painstakingly long and would delay the route, especially at peak hour, reducing it to the speed of a local bus at peak hour, which suffers from that problem.
In short, articulated buses need revised seating, but more importantly, a third door. The old Breda buses are the only ones in the Metro system apart from RapidRide buses that seem to have grasped this idea, and they greatly ease the flow of passengers and help to avoid delays a lot of the time. Their efficiency is much needed, because these buses run some of the most crowded routes in the Metro system.