Long-distance and regional transport needs are significantly different from local ones, and different land-use and activity patterns can hugely reduce transportation needs. The fact of a large country doesn't mean that individual urban areas can't be designed for mass transit or walkability.
If you can find shopping, school, recreational, and work activities within a few blocks (or at most a few miles) of one another, then a car becomes more a nuisance than a requirement. The exceptions become trips out of town -- the outdoors, visiting friends, etc.
Shopping can be dealt with through deliveries (scheduled and bundled, or online). Or local pick-up and a cart, wagon, or bike trailer.
Trades and crafts will still likely require transport, but that becomes an outlier exception.
Depending on what long-term fuel and economic trends look like, I suspect the US will see either regional high-speed rail or plain-old conventional slow rail. Aviation with expensive fuel becomes an expensive proposition. Roughly half a large jet's take-off weight is fuel, and for an efficient airliner at 40 passenger miles/gallon, a 3,000 mile flight involves 75 gallons of fuel -- at 6.8 pounds per gallon, that's 510 lb. of fuel, 2-4x the weight of a passenger. And while trains can be electrified, the options for doing so to aircraft pose a few larger technical hurdles.
If you can find shopping, school, recreational, and work activities within a few blocks (or at most a few miles) of one another, then a car becomes more a nuisance than a requirement. The exceptions become trips out of town -- the outdoors, visiting friends, etc.
Shopping can be dealt with through deliveries (scheduled and bundled, or online). Or local pick-up and a cart, wagon, or bike trailer.
Trades and crafts will still likely require transport, but that becomes an outlier exception.
Depending on what long-term fuel and economic trends look like, I suspect the US will see either regional high-speed rail or plain-old conventional slow rail. Aviation with expensive fuel becomes an expensive proposition. Roughly half a large jet's take-off weight is fuel, and for an efficient airliner at 40 passenger miles/gallon, a 3,000 mile flight involves 75 gallons of fuel -- at 6.8 pounds per gallon, that's 510 lb. of fuel, 2-4x the weight of a passenger. And while trains can be electrified, the options for doing so to aircraft pose a few larger technical hurdles.