They are putting speed signs on the chase road now, but I've seen a few 32 foot RV's chase the race vehicle at over 100 MPH, I remember Glen saying "good lord the Rv is going faster than the race vehicle".
I see no reason why the 4 wheeler can't be used to chase, a lot of teams do it, as long as you get the CB, and fire extinguisher put on it, and tow bar set up. The BLM is much more worried about glass bottles 
than two people on a four wheeler or whether you are wearing your helmet.
Steve
We are one of those RV's seen or heard of. It has a modified suspension, upgraded all-terrain/weather tires for off-road/sand/snow conditions, oversized brakes, multiple fire bottles (6), 2+ long range CBs, fire rescue gear, recovery hooks, tools, etc. These mods were done by me because it's a heavy race tow vehicle, often >30,000lb GCVW, and 17k unladen. Other than CB's the mods have nothing to do with SCTA, it's just common sense. All my vehicles are modified to suit their purpose.
The drivers of the RV are professionally-trained high-performance race-licensed drivers, in both heavy and light vehicles, with hundreds of hours of seat time. Regardless of gender. Things aren't always how they appear from the outside.
It never exceeds normal speeds on the return road, unless in an emergency with authorization. I know this because I'm sitting there several minutes waiting for it, unless I blow up, then it's right there.
The SCTA emergency crew does an excellent job, but in the end, we are all responsible for our own lives. Better have it and not need it, than vice-versa.
Why I don't I personally use a light/dirt tow? I certainly have plenty of them. If something bad happens, the driver has to stop a huge weight that has no brakes. So the driver becomes roadkill. I'd never suggest that it be outlawed, but that is an unnecessary risk IMO.
