If you plan driving to the Minnesota State Fair on Thursday, be ready to sit in traffic. Roads leading to the fairgrounds have been packed all day, although delays just after lunch were starting to subside just a tad. Still, drivers attempting travel on Como Avenue were still spending 30 minutes in traffic, fair officials said.

Even those heading to off-site parking lots are experiencing congestion. By mid afternoon, 75 percent of parking spaces at the fair's park and ride lots were taken.

Things are not likely to get better. Large crowds are expected for the sold out Grandstand show featuring Def Leppard and STYX will start showing up in a few hours.

Opening day drew huge crowds, more than usual at least by casual observation, said fair spokeswoman Brianna Schutte. "It's been a long time since I've seen an opening day like this. It's been a busy busy day."

Traffic jams on Hwy. 280, Larpenteur Avenue, Como Avenue and Snelling Avenue forced some early fairgoers this morning to get stuck in traffic for up to 30 minutes. Schutte attributed that to a high demand for parking, which saw lots that normally don't fill up until 9 a.m. to be full by 7:30 a.m.

Mainine routes saw some backups at ramp on Hwy. 36 at Snelling Avenue, I-94 at Snelling Avenue and on Hwy. 280 at Como Avenue and Energy Park Drive, said Brian Kary, a MnDOT spoksman.

"Where people experience congestion is more on the local system," he said. "We do see some backups and delays on those interchange points leading to the fairgrounds"

Contributing to the congestion was that many fairgoers are creatures of habit, she said, and went to their favorite lot. For many, that used to be on the west end of the fairgrounds. The new transportation center put in last year wiped out many of those spots, and the limited number that remained were snapped up in a hurry.

That forced many drivers to circle the fairgrounds and head to expanded lots on Como Avenue on the south end. That made Como busier than normal, she said.

Though the fairgrounds have 9,000 spots at $13 per vehicle, Schutte said that people "should not expect to get a spot." A backup plan should be to use one of the fair's park and ride lots with free shuttles to the grounds. "Or come by bicycle," she said.

By mid afternoon, 75 percent of parking spaces at the fair's park and ride lots were taken.

"It's always challenging on opening day," Schutte said. "The bottom line is that the fair does not get a soft opening. We have to work the kinks out."

State Fair express buses operated by Metro Transit were busy, too. One lot, the one on County Road 73 and I-394 filled up at 9:30 a.m., said Drew Kerr, a transit agency spokesman. He said fairgoers in the west metro can use the lot at Parade Stadium as an alternate until space becomes available. All other lots still had space as of mid-afternoon, he said.

"We've still got plenty of room for fairgoers who want to avoid congestion," he said. "Anybody heading to the fair today or during the 12-day run should consider trading time stuck in traffic for time sharing the ride with their fellow fairgoers."

Traffic was loosening around the fairgrounds just after lunch, Schutte said. But with the evening commute and a big grandstand show on tap Thursday, traffic likely will be at a crawl once again.

"People will need to be patient," Schutte said.