The only answer -- other than more dramatic answers involving discouraging more people from coming -- seems to be some form of carpooling/transit to the playa to reduce the number of vehicles if not the number of people. (This was in fact the only meaningful way to be green this year, since 90% or more of the environmental impact of the event is just getting there.)
Of course, to Burning Man, 2 or even 3 is not a carpool. That's pretty normal. More like 7, the full capacity of a minivan or RV, or a bus.
There are a few interesting ways that carpooling could be strongly encouraged.
If we don't do something like this, we'll have to take other steps to exclude people from Burning Man, beyond just making it remote, harsh, expensive and unadvertised.
- A carpool lane for entry and exodus. Be a big enough carpool and bypass those long lines. That can easily be a combined saving of 7 hours of many people's time.
Have cheaper tickets for people and require a ticket for the vehicle as well. Instead of a $250 ticket per person, make it $200 per person plus $200 per vehicle, breaking even at 4 per vehicle. Or similar formula designed to be revenue neutral.
Bus service to and from Fernley or similar place, for burners who don't have to carry a lot of stuff. Gate/Greeters at the Fernley parking lot, so bus drives right into city, bypassing gate line, and exodus line too. Well worth it just for the saved time if you don't have much stuff or can get your stuff in your camp's truck.
Want to get really technical? Gate can check IDs to count only those who live in the same state as the vehicle, since picking up those who flew in does not actually remove nearly as many vehicles from the playa -- these folks already routinely carpool, I've picked up some from the burner hostel, and this is about further reducing cars, not about being "fair." But I don't think we need to go this far.
If there were sufficient gate/greeting volunteers, you could even put one on the bus from I-80, and have tickets taken and greetings given while on 447. Then it's a burning man party bus even before you get to the playa. Your playa starts 4 hours sooner. The downside is that without enough suitable volunteers, you would have to send one back on each bus, wasting their time.
(Not much we can do about how inefficient it is to move people one-way by bus, with an empty bus going back. However, it might make sense to have the main bus stop in Gerlach -- thus never getting dusty -- and switching to some number of vans which then go to the various quadrants of the city to drop off the passengers.)
Of course, more organization of shared trucks would be a big plus.
Note that most of this need not be done by the BMOrg. All they have to do is the bless the carpoolers with a carpool lane or the modified ticket prices and the community would do the rest to organize the carpools. Possibly burners could even arrange the buses as a business (gasp) -- I think many would pay well for a bus ticket that saves them 7 hours by going in the carpool lanes.