Couldn't you plan the dive as if it were a high altitude dive, even though you are at sea level? That way, you wouldn't have to worry about ascending to that particular altitude?
You can plan it as if it were a high altitude dive, but that does not mean you were at high altitude. What matters is what actually happened on a dive and what happened after it, not the way it was planned.
I run into this sort of thing frequently in my diving, and a thread I wrote on that might be of interest:
Ascent To Altitude From Santa Rosa
While you are driving, you are off-gassing, and if you are doing a gradual ascent, especially if you are doing an increasing series of ascents, it is like doing decompression stops. In theory, you should be accelerating the rate at which you off-gas that way, and, also in theory, you should be safer because of it than if you just stayed at sea level for the same period of time.
In theory.
When I drove from Kona to Hilo and the volcano, I had that theory in mind. The drive around the north end of the island is very much like a series of decompression stops. You go up for what should be a safe amount of ascent, level off for a while, ascend again, level off for a while, etc.
Unfortunately, that theory has never been tested. I would love it if someone would take a bunch of divers on a drive like that, doing some doppler bubble imaging along the way, to see what happens.
