20 years after the last Ponca City Grand Prix, the local members of the Sports Car Club of America worked hard to have a 50th anniversary race on the very same layout as the original sports car races around Lake Ponca Park in Oklahoma. Reviewing new track safety specifications with the SCCA National Office not too far away in Topeka, officials added several walls in high speed locations and eliminated the signature feature of the original track: 55 gallon drums filled with water everywhere. Other things were added like temporary curbs and tire walls to make the track more racer-friendly. The race went off without a hitch in front of 15000 spectators on July 4th, 2011. Northern Oklahoma has an annual SCCA Regional/National again, the only one in the U.S. held on a temporary circuit.
Here's a description of the real track from na-motorsports.com:
Ponca City was a 1.5-mile park course that used the roads of Lake Ponca Park in Ponca City, OK. Although the roadways still exist (La Cann Drive and Checkstand Road), they are no longer used for racing. The Ponca City Grand Prix was held annually on the July 4th weekend from 1961 until the early 1990s. Like its sister park track, Lake Afton, it succumbed to increasing safety standards: contemporary photographs show cars racing past, and occasionally hitting, unprotected trees. Its traditional July 4th weekend date has since been taken by Hallett.
This track was created using Bob's Track Builder and many of the free downloads from racedepartment.com (Thanks to BTB programmer, Ennis, Krunch the sky guy, 6e660, and the great folks who put their things up for free there, they make life a lot easier). The tutorials and threads from racedepartment.com were also indispensable...the "search" function answered almost all of my questions!
NOTE: BTB crashed whilst working on this project near the final stages. I was adding several details like spectators, many objects I created myself, and fixing little things here and there. So the track will look like a ghost town forever. Known bug: trees look terrible when details are not set to full. Everything else should be happy.