It takes a lot of time to unload a large truck and sort and store its contents. This means that trucks tend to make deliveries during the daytime, when the cost of paying people to unload trucks is relatively low.

If, however, the process of unloading trucks and handling their contents becomes automated, overnight deliveries may become much more common. At night trucks are able to avoid being caught in, and contributing to, traffic jams.

Making more deliveries in the evening or overnight may, in turn, lead to an increased demand for electric trucks. Electric trucks are far quieter than diesel trucks, which is obviously an important trait for nighttime delivery vehicles. They can also be operated relatively cheaply overnight, given the generally much lower price of nighttime power.

If – an enormous if – electric trucks do not need batteries that are heavy, bulky, pollute, and frequently need to be recharged, they can also operate many times more efficiently in general than can diesel trucks.

This is mainly because electric vehicles do not pollute city air, and because electric motors and the power plants that generate their electricty can be several times more energy-efficient (and potentially far more eco-friendly) than internal combustion engines. But it is also because electric vehicles can have regenerative breaking systems that recapture some of the power they expend, and because they have dynamic break systems and motors with very few moving parts, and because they have far stronger torque that helps them climb hills.

Unfortunately, the batteries needed to power trucks are too heavy, bulky, polluting, and range-limited*. This is especially true of batteries for large trucks**, which are the most cost-efficient and eco-friendly types of truck — and which would remain generally the most efficient types of truck even if all trucks were to become self-driving.

[*There may be three main options for dealing with batteries’ limited ranges: slow-charging, fast-charging, or battery-swapping. All three options are problematic. Slow charging is problematic because the nighttime is short, so to spend several hours charging a large truck battery is a waste of precious time. Fast charging is also problematic, because it requires a very large amount of energy at one time, which would then increase peak nighttime energy demand for the grid when lots of trucks are fast-charging their batteries at the same time. If, for example, the wind stops blowing at the same time that many trucks are using wind power to fast-charge their large batteries, power might need to come from fossil fuels, making them much less environmentally friendly. Moreover, if fast-charging stations were used during the daytime too – which presumably they would be, because why spend the money to build fast-charging stations if you are only going to use them at night – it could then lead to increased peak demand in general, which would be both inefficient and environmentally problematic. Battery-swapping stations, then, might be the best option — but building them is easier said than done, given the huge size of truck batteries. Even then, however, they would still not overcome any other issues associated with battery use in trucks.]

[**To quote The Globe and Mail: “Battery powering of heavy duty vehicles may not be expedient. To match the range provided by the diesel fuel tank of a typical long-distance heavy-duty truck, which when full weighs about a tonne, a heavy-duty battery-powered electric-drive truck would have to carry almost 30 tonnes of battery, which is much more than the average payload of heavy-duty trucks.” ]

Barring a breakthrough in battery technology, this only leaves one other option: electric trolleytrucks. These get their power from overhead power wires, somewhat like streetcars do. They then use small batteries in order to travel short distances away from these overhead wires.

Some cities already have large wire-powered networks. Vancouver, for example, which is a city especially suited for electric vehicles given its hilly terrain and cheap, clean, hydropower-generated power, has close to 300 kilometers of wired roads, which it uses for trolleybus transit.

Luckily, trucks making overnight deliveries can avoid the challenges that have thus far prevented trolleytrucks from being commonly used. The main challenge for trolleytrucks has been city traffic. Because they can only travel a few kilometres away from their power wires, they cannot handle the risk of getting caught in stop-and-go traffic.

Overnight, however, the lack of traffic and much longer green light-red light cycles removes this risk. It also means that should a mistake occur that does leave a trolleytruck stranded away from its power wires and out of battery power, it could simply wait for a support vehicle to come and charge its battery, without causing any road traffic blockage as would occur if it ran out of power during the day.

This extended range away from the wires at night also helps solve another main challenge: lots of people find trolley wires aesthetically unappealing. The ability of trucks to travel further away from the wires at night means you don’t need as many streets wired. You might even be able to get away with only having some highway corridors — where aesthetics is not a problem – wired. The trucks could run on the wired highways during the daytime, then run mostly off-wire overnight to get a few km in the city to make deliveries further from the wired corridor.

A final, hugely significant challenge, which trolleytrucks must face regardless of whether they run during the day or night, is the cost of intermodal cargo transfers. Even if a trolley wire-building spree were to occur, most roads will remain unwired for the foreseeable future. As such, for trolleytrucks to be competitive with diesel trucks, the cost of transferring cargo between trolleytrucks and other vehicles – notably, diesel trucks and trains – must fall. Trolleytrucks being more efficient than diesel trucks will not be sufficient to make them ubiquitous. This can be seen already by looking at the fact that trucks transport much more freight than do railways, despite railways being more efficient than trucks.

If autonomous loading and unloading of trucks, and autonomous sorting and storing of trucks’ cargo, dramatically reduces the cost of intermodal cargo transfers, as seems likely to occur (or at least, plausible), then we might expect the use of cargo railways and of trolleytrucks to increase relative to the use of less efficient diesel trucks.

Indeed, if the automation of intermodal transfers serves to increase

railways’ share of freight transported relative to trucks, one result may be that a larger share of trucking will take place in hilly or urban areas where railways are less competitive. And, since hilly and urban areas are precisely the areas where electric vehicles are most useful — in hilly areas because of their torque, dynamic breaking, and ability to go through tunnels without spewing exhaust that requires ventilation; in urban areas because of their low air and noise pollution – this might further increase the use of trolleytrucks (and trolleybusses!) relative to diesel.