How about changing the stop light to a roundabout? The Washington DOT has installed a number of those to replace high-accident intersections.
Recently a nearby church was converted to a private school. The city engineers ran traffic simulations, and concluded that they could require the school to install stop signs, with solar flashers, at the nearest arterial intersection. But they couldn't require anything more expensive. Apparently the simulations showed that a delays with a 4way stop were within city wide traffic flow targets.
The stop is a block from an I5 interchange. So locals have speculated that if the backups get too long, DOT might step in and fund a stop light, or even a roundabout. But for now the 4way stop seems to be working.