One of the main claims of the Energy Decline movement is that trucks will suddenly stop running once diesel becomes scarce. There was a book written about this problem, entitled When Trucks Stop Running.
Since that time, battery-powered trucks have been introduced by Tesla and other manufacturers and are commercially available now.
The problem with battery-powered trucks is that they have a 200 mile range or so. That range is insufficient for long-haul trucking. However, that range IS SUFFICIENT if we use inter-modal transportation. I am proposing that we could switch some of the truck traffic to rail as diesel becomes scarcer. Instead of using long-haul trucking, we would use short-haul trucks to deliver the cargo to the nearest railroad, and then use other short-haul trucks to deliver the cargo from the railroad to its destination. In which case, the range of battery-powered trucks is sufficient.
Take a look at this map of the railroad network in the United States. You will notice that almost everybody lives within a 200 mile radius of a railroad. There are some rural areas in Nevada, Idaho and Wyoming which are not within 200 miles. However, those areas are extremely sparsely populated, consisting of very small towns spread far apart. I would estimate that approximately 99.9% of the population of the continental US lives within 200 miles of a railroad (the proportion is certainly higher in Europe and Asia, which are more densely populated). The one major exception is western Florida, but a railroad could be built there if necessary.
Thus, we could simply switch modes of transportation and use rail more often. A combination of current railroads and 200-mile trucks is sufficient to reach almost everywhere in the country.
Railroads do not require diesel for their propulsion. About 30% of the railroads in the world are powered by overhead electricity lines, and many countries have electrified their entire railroad networks in less than 20 years.
The only reason long-haul trucking is used at all is because it’s often cheaper than using trains part of the way. If you want to use a train part of the way, then you must drive the truck to the nearest railroad, offload its cargo onto a train, offload the cargo from the train and back onto another truck, then drive that truck to its final destination. The added step of loading and offloading takes time and money. Oftentimes, it’s cheaper just to drive a truck the whole way. Furthermore, the route is sometimes more direct by just driving a truck the whole way.
However, that calculus changes when diesel is more expensive. Suddenly, it becomes cheaper to use rail part of the way despite the additional step of loading and offloading. As a result, long-haul trucking could become much rarer as diesel becomes more expensive.
Of course, there are a few rare circumstances where long-haul trucks would be irreplaceable. Think of those isolated towns in rural Nevada. In those rare cases, we could use biofuels or synthetic fuels for long-haul trucking. I would estimate that less than 0.01% of freight delivery in this country is not amenable, at all, to rail or inter-model transport. Although biofuels couldn't scale up to power everything, they could certainly scale up to power those rare cases.
Finally, I should point out that the industrial revolution and first-world countries were built using railroads, not trucks. Back in 1910, the US had a railroad network about 3x longer than today, and long-haul trucking was non-existent. Anything possible in 1910 is still possible now. Long-haul trucking is not really necessary at all. I once lived in a tiny isolated town of a few hundred people, which still had an old railroad depot (long since abandoned). This is common almost everywhere in rural America.
Thus, the solution to diesel becoming more expensive is to use electrified rail more often.
All of this assumes that hydrogen fuel-cell trucks are impossible, as was widely assumed in the energy decline movement (here). However, long-haul fuel-cell trucks were introduced late last year and Hyundai is scaling them up. In which case, long-haul trucking could continue without diesel.