As Ridgefield grows, its charming, walkable downtown is earning another reputation: traffic-filled.The state’s fastest-growing city has seen an increase in downtown traffic in recent years, and some ongoing construction mixed with booming enrollment at downtown’s Union Ridge Elementary School and View Ridge Middle School have left the city with even longer backups.The city started doing some sewer work the week of Oct. 17 at the intersection of Pioneer Street and 45th Avenue, which sent detouring drivers through downtown.“That detour has made what was a difficult traffic situation even worse before and after school,” said Bryan Kast, the city’s public works director.City and school district officials both heard complaints from residents. Discussions between the two sides about alleviating traffic issues downtown started in September, according to Ridgefield Superintendent Nathan McCann. A few days after construction started, the two sides agreed to put a flagger near the schools to ensure that the area is safe for students.The flagger, who is paid for by the contractors doing the sewer work, will remain there for the duration of the project, which is expected to end on Nov. 11, Kast said. He added that the city and school district are discussing how to keep a flagger on duty after the work is finished. Both Kast and McCann said they’re confident they’ll figure out how to keep someone out there for the duration of the school year.