If streetcars are proven to attract more riders than buses, then why doesn’t every American city make like Portland and start laying track? For one, streetcars are expensive. Seattle hiked its regional sales tax by 5 to 10 percent in order to pay for its transit projects. Second and perhaps most importantly, streetcars can only absorb a small fraction of any city’s daily transit load. King County Metro, the county’s transit authority, continues to operate 1,835 buses on 215 routes. So while streetcars are environmentally friendlier, quieter, and some say more aesthetically pleasing than buses, they remain something of an outlier, an experiment. And for every passionate defender of rail travel, an equally fervent – and probably more practical – advocate of improving existing buses waits in the wings.