I did it once a few years ago with a carload of friends, and vowed never to do it again because it took so long just to get to the start of the display... and then it felt a lot like sitting in traffic, with better decorations. We saw people walking alongside the cars, and they seemed to be going a lot faster--but then we realized they were breathing in all the exhaust from the long line of vehicles.
Well, it turns out that for the first two weeks this year, the path is closed to cars but open to pedestrians! Apparently this is to demonstrate the city's commitment to a "greener L.A." I say, Hallelujah! The pedestrian-only nights are Nov. 24-Dec. 7th, from 5 to 10 pm. On Dec. 5-7, there will also be Family Fun Mini-Fair along the festival route.
Parking and shuttle info from the official website:
Visitors may park at the L.A. Zoo parking lot or the parking lots on the south side of the festival near the Merry-Go-Round, or the lots near the pony rides. Parking will be on a first-come, first-served basis. Walkers are encouraged to wear comfortable shoes and to dress warmly to walk the full one-mile route each way. It is also recommended that walkers have outerwear, as it can get chilly. Shuttles will assist in bringing guests from the remote parking lots to the route entrance.