From the GSCA website:
Track Hours
Tuesday.................................................. 3:00 pm - 4:00 pm*
Wednesday & Thursday..........................
9:30 am - 6:30 pm
Friday .................................................... 8:00 am - 8:00 pm
Saturday................................................. 8:00 am - until the end
The track gates are locked for the night. No one is allowed to remain in the track after the gates are locked.
Hope this helps!
Shari