The biggest problem for bikes is two things:
The SCCA has specific requirements for race tracks to be certified for SCCA racing.
Motorcycle racing has nothing more than a loose group of individuals that toss around ideas on specific safety aspects. Many AMA tracks do not meet FIM requirements as they are published in the FIM books over the various years.
So, the tracks get very ambiguous requests from riders and organizations for motorcycling. The SCCA has specific standards that have to be met in specific periods.
Dave makes an excellent point. To be a little more specific, there is a reluctance (gross understatement) by the sanctioning bodies to specifically state acceptable safety requirements. Why? Litigation. Like everything else in the world, follow the money. Specific safety requirements cannot address every concievable situation and this leads to an incurred liability by the sanctioning body. I was informed of this by one of the 4 SCCA safety inspectors in the country, and the only one with FIM training. Ever read the SCCA event regulations? They are 95% insurance requirements, 5% facility/spectator/equipment regs. They're online and make for some interesting reading if you're into that sort of punishment.
As for the cost of track surface rehab, A standard asphalt mix wont work. Track surfaces deal with shearing forces under braking and acceleration that develop loads you will never see anyplace else. Separation of the final course from the base course is a common form of failure, although poor subbase/poor mix design/failure to maintain are also worthy of consideration. Poor placement of materials/failure to allow proper curing can also contribute to the issues, just ask Autobahn. Or Barber. How the pavement fails (bumps vs alligator cracking vs ?) are good indicators of the design issue to be addressed. Patching opens a whole new can of worms.
Tracks have been rehabbed using a mix design "created" by insightful amatuers and worked. They have also failed miserably. As a counter point, I know of track surfaces that were designed by professional engineers and still failed. Climate is a huge factor. So is placement. A proper mix design starts with (typically) State DOT mixes, and is then modified to address vehicle specific load requirements, then lab tested. Any adjustments needed during the lab test period are made. Following that a track owner can either A) Pave. or B) Run a test pave to teach the crew doing the work how to place the material properly and evaluate placement methods/field adjustments, and then pave. Add the cost of removal/subbase prep into this and the costs start to add up.
Sheesh...I gotta stop drinking so much coffee.
As for track walks, gotta love 'em. I'm always amazed how much stuff I ride over that never even bothers me. Super Dave and I ran laps at BHF a couple of winters ago with Tom and then manager Pauli to check the surface and talk about maintenance issue. Lots of credit to former owner Ray Irwin, Tom and Pauli for the improvements they managed to accomplish. With a bit of luck the new owner will be successful too. He has a great staff to work with.
I dont post often, but when I do, I REALLY post!