Runners and musicians alike will take over the streets of San Diego this Sunday — 20,000 runners to be precise — when the Rock ‘n’ Roll Marathon comes to town. The 12th-annual marathon set to rock music concludes three days of health and fitness events. “It’s essentially a 26.2 mile block party,” said event manager Kari Logan. A new element of this year’s race is the Rock ’N’ Roll Relay. In the relay, 400 teams of four will complete the course for awards in five different award categories. “We wanted to add a little spark to the event. It’s a good opportunity to give the non-marathon runner a chance to participate in the event,” Logan said. “It will hopefully open the door to making them want to run a marathon one day.” But the Rock ‘n’ Roll Marathon is not all about the running. A total of 42 bands will set up at stages along each mile of the course for runners and spectators to enjoy. Forty high school cheer squads will also urge on the runners, competing with each other in the “Spirit of the Course” contest. “Pacific Beach and Mission Bay are the best spectator spots because the neighborhood has taken ownership over the past few years,” Logan said. “The residents come out and have their own block party.” Traffic will also snarl across town, and participants should plan an extra one to two hours for travel and expect delays similar to Super Bowl Sunday. The race takes off at 6:30 a.m. at Sixth Avenue and Palm Street in Balboa Park and finishes at the Marine Corps Recruit Depot in Point Loma. The 15 to 20 elite runners will roll in within two hours, followed by the front of the pack an hour later. A concert will end the celebration at 1:15 p.m. at the Marine Depot. Bedford Grove will open the concert, followed by ’80s fusion band English Beat. The show is free and open to the public. Runners have also raised approximately $8.2 million this year for the Leukemia & Lymphoma Society’s Team In Training program. In the past 12 years, the race has garnered approximately $142.8 million for cancer research. The weekend’s festivities start with the health and fitness expo on Friday from 11 a.m. to 7 p.m. and Saturday from 9 a.m. to 5 p.m. at the San Diego Convention Center. The expo features more than 100 exhibits, discounts on fitness apparel and accessories. Those interested in being part of the race without having to break out their running shoes can register to be a volunteer on the marathon’s website at www.rnrmarathon.com. Individual volunteers can help out at the expo and the start and finish lines, and groups of 10 or more can sign up to hand out water at various water stations along the course. “If people want to get involved without running, they can volunteer, or simply get out on the street and give high fives and make their own signs and cheer on the runners,” Logan said. The marathon route will close multiple roads throughout the area. Highway 163 is the only major highway that will be closed on race day. The Southbound 163 will be closed between Interstate 805 and downtown from 2 a.m. to 12 p.m. Sunday. Interstate 5 between Sea World Drive and downtown and Interstate 8 between Friars Road and Interstate 5 will also be impacted. Residents are encouraged to plan ahead and avoid these areas during the race in order to avoid delays. For a list of all affected roads and other road and freeway ramp closures, visit www.rnrmarathon.com-/course_info/road_closures.html.