Just a thought on how to increase car counts:

How 'bout a driver referral program. For every new driver a current driver brings to the track they get $20 off the entry fee per race for the first year.

Eg. Bring a new driver to the first race and get $20 off the entry fee. Bring the driver again the 2nd race and get $20 off again...continue until the end of the year.

Make it even more interesting $500 year end bonus to the person who brings the most new drivers. Ill bet that starts bringing in more people. Maybe a trophy too ha ha