The light-rail line from SeaTac to Federal Way should be built mostly along Interstate 5, instead of over Highway 99, the Sound Transit board decided Thursday.
The unanimous vote gives the I-5 alignment preferred status in the final environmental-impact studies before a final board vote in late 2016. That’s roughly when the public is expected to consider a hefty tax increase to fund more than $15 billion in regional transit extensions, including most of the Federal Way line.
A $1.4 billion freeway route is supposed to save $300 million in construction and land costs. It’s also backed by all four suburban cities in its path, SeaTac, Des Moines, Kent and Federal Way, whose leaders are loathe to inflict a construction mess on Highway 99, or hurt small businesses through property takings.