From 10 AM every day during the festival, you can catch a complimentary shuttle bus from Austin City Limits vacation rentals to the festival grounds in Zilker Park. Board the bus at the corner of 4th and Guadalupe in downtown Austin. Buses are also on hand to bring you back to Republic Square after the festival each night, with the last departing at 11 PM.
A special illuminated "hike and bike" trail runs from the city to the festival grounds. As there are extensive bike racks at the park, you just need to bring your bike lock with you to enjoy one of the most efficient ways to get to Austin City Limits. Instead of sitting in the traffic that tends to move at a glacial pace during the festival, festival veterans often opt to bike.
If you must drive, there is paid parking available at One Texas Center and the Palmer Event Center, both around a mile from the park. While taxis will be on hand for pick up and drop off at the park entrance, you may have to wait along with the crowds. Ride Austin can be a useful alternative to hailing a cab.