The 20th anniversary Colfax Marathon will force detours and delays for some Regional Transportation District bus and light rail services Sunday morning.

The event will reroute or suspend portions of several lines from 5:30 a.m. until approximately noon May 17 as runners move through Denver and Lakewood. Customers should plan extra travel time and check schedules in advance.

D and H lines will skip Colfax at Auraria Station through the Downtown Loop stations on Stout and California streets, the agency said. Those lines will continue serving 10th-Osage Station and reroute via Auraria West Station, Empower Field at Mile High Station, Ball Arena-Elitch Gardens Station and Union Station.

The L Line will not run during the event. Riders should use bus Route 43 instead.

No rail impacts are expected Saturday. Delays are possible on D, E, H and W lines throughout the day because of heavier traffic at Union Station.

On the bus side, routes 20 and 24 will see a minor detour Saturday from 9 a.m. to noon for the Colfax 5K. On Sunday, a long list of routes will detour where necessary but will cross the course when safe: 0, 1, 6, 8, 9, 10, 12, 15, 15L, 16, 19, 20, 24, 28, 30, 38, 40, 43, 44, 48, 51, 52, 76, 83L, ART and FREE MallRide.

Scheduled connections could be affected. RTD advised riders to use the agency’s trip planner before heading out.