Practice for this weekend's Baltimore Grand Prix doubleheader featuring IndyCars and American Le Mans Series cars has been delayed by revisions to the two-mile, 12-turn temporary street circuit. The revised schedule currently calls for the IZOD IndyCar Series cars to take to the track for the first time from 4:00-5:30 p.m. ET, with ALMS cars following from 5:50-7:00 p.m.

Delays were caused because of safety fencing that was taken down in preparation for Hurricane Irene last weekend, which is being re-installed, track officials said. Work also started late in the section between Turns 7 and 10, which border the Oriol Park baseball stadium, due to the venue hosting a Major League game on Thursday afternoon.

The first practice session for the USF2000 series was originally scheduled to start at 8:00 a.m. local time, but was delayed to allow track workers to finish installing barriers around some sections of the circuit. IndyCar president of competition and operations Brian Barnhart said additional changes may still be necessary.

Drivers, including Graham Rahal, have expressed concerns about some elements of the track, including the railroad track crossing.

"Obviously, the fans and drivers are disappointed with the delays, but there's always some growing pains with a first event," the Chip Ganassi Racing driver told IndyCar.com. "Without a doubt they'll get it sorted. I think if this event is around for many years, it has the potential to be fantastic.

"If they could smooth out the railroad tracks on Pratt Street, which is the front straight, then the rest of the track has the making for a fantastic place to go racing."