The old Benson Ave Bridge over I-405 is coming out tonight, to allow the freeway to be expanded with an extra lane each way. The bridge removal will require that the entire freeway be closed both directions from starting in a few hours. The freeway will reopen by 11:00 AM Sunday. Note it will be closed all day Saturday, so plan your driving carefully to avoid traffic jams. We’ve tried to get motorists to take I-5 and I-90, but much freeway traffic will also be detouring through Renton.
Here is more info in the Seattle Times.