I cannot speak to east of Seattle but for significant portions it is grade separated.

Of the 3 stops where it isn't, it has it's own lane on a major thoroughfare and only chances an errant driver crossing an intersection.

Now for the Seattle Streetcars, those are a different story. For the most part, they have a dedicated lane so they breeze past traffic, but could get caught if traffic is especially bad.

This happened in the 2016 Washington State Treasurer election

https://ballotpedia.org/Washington_Treasurer_election,_2016

Duane Davidson (R) won against Michael Waite (R) after 3 democrats split the vote in the primary:

    Republican Duane Davidson 25.09% 322,374
     Republican Michael Waite 23.33% 299,766
     Democratic Marko Liias 20.36% 261,633
     Democratic John Paul Comerford 17.97% 230,904
     Democratic Alec Fisken 13.24% 170,117

I'm not sure any of the alternative systems would have actually given a different result. Yes, the democrats have a majority of the vote, but transfer of support between members of a party is never perfect.

I'm also not sure if this is enough of a problem to try to solve preemptively, if there's one example from four years ago from a state-level election.

If outcomes in general are better, I'll take the risk that they're occasionally worse.