Travel recommendations:
- Bring plenty of food and water for potential delays.
- Park your vehicle for the duration of your stay. Driving from site to site increases traffic congestion.
- Ride the free shuttle buses to enjoy Yosemite Valley most easily once parked.
- Consider arriving early and staying late, or visiting Yosemite during the week.
- Enjoy the entire Yosemite region - consider visiting the surrounding communities of Mariposa, Groveland, Lee Vining and Oakhurst.
- Ride a YARTS bus to enter the park on Hwy 140 from El Portal or Hwy 120 from Lee Vining.
- Congestion is greatest in Yosemite Valley and at Glacier Point. It is especially heavy on weekends.
- Parking lots are generally full by 12:00pm, and sometimes earlier.
- Vehicles on roadsides must use designated turnouts and pull off the road completely. Do not park on vegetation.
- After reaching the one-way road on the Yosemite Valley floor, the only route to avoid the areas of heaviest congestion is the left-hand turn labeled for Highways 140, 120 and 41.
http://www.nps.gov/yose/planyourvisit/traffic.htm