SANTA CLARITA, Calif. - The sounds of high-performance car engines filled the air Sunday as thousands of fans, friends, and car enthusiasts headed to the Los Angeles suburb of Santa Clarita to pay tribute to Paul Walker at the site where the

Fast & Furious

actor died in a car crash.

The memorial, planned through social media, was to begin at noon, but mourners began arriving hours early to leave flowers, candles, stuffed animals, and other tributes. Throughout the afternoon, thousands of people, including families with children, dropped by.

Many arrived in cars built for speed, and the sounds of engines revving echoed close to where Walker and his friend died Nov. 30. The event was expected to conclude Sunday evening with a cruise through the area 30 miles northwest of downtown Los Angeles.

Walker, 40, was killed when the Porsche Carrera GT he was riding in smashed into a light pole and tree and then burst into flames. The actor's friend and financial adviser, Roger Rodas, who was driving, also died.

On Sunday, Los Angeles County sheriff's deputies directed often-heavy traffic as mourners passed by the crash site on foot and in cars. At one point, traffic backed up for miles, the sheriff's department said on its Twitter feed, adding that some illegally parked cars had to be towed.