Normal buses also have to deal with the consequences of running within a stream of automobile traffic.
To avoid snarling traffic, buses must pull off the right of way, in a 'bus pullout'. It prevents them from slowing automobile traffic, but has significant consequences for the bus. First, the bus must slow down and turn out of the travel lane rapidly, jolting passengers on board. Second, the bus must wait for a gap in traffic to re-enter the lane, which
substantially slows the bus.
The EmX suffers from none of these flaws. The EmX doesn't quite have it's own lane, but it has a 'BAT', a 'Bus
and Turn' Lane. No cars permitted, unless they are turning into either a
curb-cut, or at an intersection. Not quite as good as a full lane, but
certainly better than a shared lane.
It also seems to have been cheap and easy to create. It looks like the EmX's BAT lane used to be the 'safety area' at the edge of a high-speed arterial. The safety area is a 8' wide stretch of pavement between the outmost travel lane and the curb, and is designed to let drivers veer several feet without either running off the road or running into anything. More than wide enough for a lane, and many safety areas vanish as they are re-striped as lanes as traffic volumes grow.