SAN DIEGO -- The most congested rush-hour spot in San Diego County in 2009 was a stretch of state Route 78 in San Marcos, according to a newspaper analysis published Tuesday.

Eastbound state Route 78 at Barham Drive was backed up during rush hour 243 days last year, or just about every workday, The San Diego Union-Tribune reported. The length of each slowdown averaged more than four miles, according to state traffic data analyzed by the newspaper.

Northbound Interstate 5 at Via de la Valle in Del Mar had been the county's worst bottleneck for 2006, 2007 and 2008 but dropped to No. 7 last year. Caltrans officials point to the recent extension of car pool lanes from Del Mar north to Manchester Avenue in Encinitas to explain the improvement, the Union-Tribune reported.

San Marcos Mayor Jim Desmond said his city is working with Escondido officials and others to improve the Nordahl Road interchange, just east of Barham Drive, the Union-Tribune reported. San Marcos has committed $5 million to the project and given an additional $4 million to Caltrans for improvements on Route 78 near Cal State San Marcos.