Drivers heading south on I-405 Monday night (Nov. 10) might face unexpected congestion.

The state will close the carpool lane and far left lane of southbound I-405 near I-90 starting at 7 p.m. – the tail end of the commute – for emergency repair work.

An unsafe dip appeared in the carpool lane after this weekend’s rain. Construction crews plan to make repairs swiftly and reopen the two lanes to traffic before the 5 a.m Tuesday commute. That leaves just one lane on southbound I-405 for traffic during the work.

For the safety of drivers, crews patched the dip earlier on Monday, but needed time overnight for a permanent repair.