The temporary traffic pattern on Frazier Avenue between Barton Avenue and Market Street will continue with the closure of the two inside lanes until next Monday at 7 a.m, city officials said.
The modification is in place using temporary traffic control devices including drums and signs.
Officials earlier used the "lane slimming" pattern only on weekends.
The shift began after a car ran up on the curb at Frazier and Forest, killing a mother and son and critically injuring the husband/father.