Expanding light rail is the centerpiece of the $50 billion Sound Transit 3 measure voters will consider in November.
Many transit advocates support it, but not all.
"I'm a carless person who lives in Capitol Hill," said Troy Serad of the group Smarter Transit.
Serad said his commute to Lakewood, now by express bus, would get worse if he was funneled onto light rail for a portion of his commute because he'd exchange point to point bus service for a train that makes lots of stops.
"It's going to extend my commute. I'm going to be paying for this commute until I'm a very old man," Serad said.
Smarter Transit instead suggests bus rapid transit.
Buses run in dedicated lanes and go more places because systems are cheaper to build.
The group also advocates expanding HOV lanes and existing commuter rail.
Light rail, says Mark Ahlers of the group, is too expensive for the number of people who will ride it.
"It strikes me as a bizarre disregard for costs," Ahlers said.
Bus rapid transit is proposed in ST3 for the I-405 and SR522 corridors.
But Sound Transit's Bruce Gray says light rail is better for denser places where buses get stuck in traffic.
"It is expensive to build these systems. But once you're up and running, it costs a lot less to carry riders on the light rail system than it does on the bus lines," Gray said.
Gray said that's because one operator can drive a lot more passengers on a train than a bus.
Smarter Transit is not the official "no" campaign for Sound Transit 3.
That is expected to launch soon.