Light rail systems are often a Goldilocks-style compromise between the flexibility of automobiles and the efficiency of trains. The problem is, nobody likes Goldilocks.

If, for instance, Doug Ford is elected premier of Ontario this spring, it is not unlikely that he will cancel the Hamilton, Hurontario, and Sheppard LRTs, leaving only the Eglinton Crosstown and Finch West projects that are already underway. And Toronto’s mayor and city council already voted last year in favour of the suburban Scarborough Subway Extension, over an alternative plan to build that line as an LRT and then use the money saved to help fund an Eglinton East LRT.

On the autonomous vehicles front, meanwhile, a number of significant barriers to entry remain. These include: LIDAR (still very expensive, and still struggles with snow); LIABILITY; the fact that people already own conventional cars; the fact that autonomous cars (even electric ones) still cause traffic and environmental harm; and the risk of autonomous vehicles being used in a terrorist attack (for e.g. if driverless cars are common, a single bombmaker might be able to load numerous vehicles with explosives, and detonate all of them simultaneously at a crowded urban location). And of course there may also be a societal hesistancy to adopt widespread driverless cars.

Because of these barriers, it seems plausible that the partial use of autonomous vehicles will occur before they become fully adopted. Consider, for example, two potential partial usages: autonomous parking lots, and autonomous overnight cargo deliveries. Both of these may not be subject to the barriers listed above:

—LIDAR may not be a challenge for autonomous parking lots, as within a relatively small, mapped area equipped with sensors (the parking lot), cars could drive autonomously without LIDAR. Overnight delivery vehicles might also be able to run without LIDAR, as they could drive at a very slow speed, and stick to running a relatively small number of high-demand routes

—Liability may not be a challenge either, as the parking lot could have no pedestrians or human drivers in it, and its cars could drive at slow speeds. Overnight delivery vehicles could also drive at slow speeds.

—the fact that people already own conventional cars is not a barrier to overnight cargo deliveries, and may not be a barrier to parking lots either. Some companies are even attempting to develop vehicles that can, in effect, tow a conventional car autonomously to and from parking spots

—the fact that autonomous cars still cause traffic and environmental harm may not be a barrier: autonomous parking lots can reduce traffic and pollution if they are located at (for example) train stations, thereby making it more convenient for suburbanites to use transit. And overnight deliveries might cause fewer diesel trucks getting stuck in daytime traffic jams, which create air pollution and other costs

—restricting autonomous vehicles mainly to limited areas like special parking lots, or special times like very late at night, could make it much more difficult for them to be used in a major terror attack (whether a car-bomb/truck-bomb attack or driving a vehicle into pedestrians, involving multiple vehicles simultaneously) as it would then remain suspicious for a driverless truck to be loitering in a crowded urban area

—special autonomous parking lots, and perhaps also overnight autonomous cargo deliveries, are much less likely to be subject to a societal hesitancy towards their adoption

LRTs in particular may benefit from autonomous parking lots and/or autonomous overnight delivery vehicles. Autonomous parking lots may promote transit usage in general, if the parking lots were located at transit stations. But perhaps LRT would benefit from them more than heavy rail would, as the flexibility of LRT relative to heavy rail could allow LRTs to directly access more of these parking lots.

For overnight cargo deliveries, LRTs could be the ideal vehicle to be used autonomously. LRTs are electric and therefore relatively quiet, and being quiet is crucial for overnight usage in cities. Also, electricity prices are cheaper at night than they are in the day (particularly in Ontario, given that the province’s nuclear and wind power cannot shut off at night). And, of course, they are much cleaner than non-electric (or even electric) trucks. In addition, an LRT, unlike heavy rail, could more often travel directly into a building or parking lot to load/unload its cargo.

One main problem that has prevented cargo light rail in the past (outside of a few exceptions, for example in Dresden where a cargo tram has run) has been that trains have less surface friction than wheeled vehicles, so it is difficult for an LRT carrying a heavy amount of cargo to accelerate and decelerate constantly in cities in order to stop for red lights, passenger stops, and — if the LRT is not operating in its own separated lane — cars. At night, however, there are far fewer cars or passenger LRT stops, and green light-red light cycles could be made to run for far longer lengths of time in order to minimize the number of times an LRT has to stop.

With autonomous vehicles, then, LRTs may no longer be only a compromise between heavy rail and autonomobiles, but instead might excel at complementing autonomous parking lots, or being used autonomously to deliver cargo.

What does this mean for Toronto? Well, as mentioned earlier, it is possible that all but the Eglinton Crosstown and Finch West LRT plans may be cancelled as a result of the coming election. The Eglinton and Finch LRTs, as it turns out, have something in common that could be relevant to this discussion: they are next to the city’s two major hydro corridors, the Finch Corridor and the Gatineau Corridor. These corridors could be used as autonomous parking lot systems that are directly accessible to passengers using the LRTs, as well as accessible to passengers using other corridor-adjacent transit stations like Finch Station and Kennedy Station. They would also be accessible to cyclists using the bicycle paths that already exists within these two hydro corridors.

If you look at Finch subway station (map above, picture below), you will see that it already has a large parking lot, 1.3 km long and 90 metres wide, within the Finch hydro corridor to both its west and its east. I propose that this lot be extended much longer, to reach north of the Finch West LRT, as an autonomated parking lot corridor. This corridor would mostly remain separate from road traffic and pedestrians, though not entirely separate: it would have to cross north-south streets, and would also have to use bridges on Finch in order to cross topographical barriers like G Ross Lord Park. But that would still be much less of a challenge than a widespread adoption of autonomous vehicles. The Finch corridor is about 210 metres north of Finch in most places, and in some places (such as west of Jane, or west of Bathurst, or between Dufferin and Keele) it widens to connect to Finch Avenue directly.

The Gatineau Corridor, meanwhile, intersects with the Eglinton Crosstown just west of Victoria Park, and also (via the narrower Scarborough RT corridor; see bottom image below) at the Crosstown’s terminus station, Kennedy Station (which is also a station on the Bloor-Danforth subway, Scarborough RT, and Stoufville GO train). If the Eginton East LRT extension to the Crosstown is built, its terminus would also be by the Gatineau corridor, at U of T Scarborough campus.

The corridor could be relatively quiet, since the cars parking in it could travel slowly. It would not be an eyesore; or at least, not more of an eyesore than the hydro towers are themselves. It would also, ideally, be “parking lot neutral”; in other words, by creating more parking on the hydro corridor, it would allow you to convert some existing parking lots elsewhere into buildings/parks/etc. It would promote an increase in transit ridership. And the corridor could also be used, seasonally, as a “bicycling highway” that would be usefully located next to the autonomous parking lot. This could be acheived by simply having a portion of the hydro corridor’s lanes be designated for cycling instead of parking during the warmer months of the year. This could be a transit option that both the suburban, car-driving Ford Nation and the latte-drinking downtown bicycle-lovers could enjoy.