I don’t know specifically if the DC Metro is less efficient than EVs, but there are a few things that drastically reduce public transportation’s efficiency vs cars.
Public transportation vehicles are very heavy, and thus require a lot of energy to move. This is generally efficient when they’re full, but
Public transportation is rarely full. Based on my experience with the DC metro, many trains run nearly empty outside of commuting hours.
Public transportation routes are indirect. I used to cover about twice as many miles on the Metro as I would taking surface streets to my job. That’s more energy to frequently accelerate and decelerate my body mass without actually always getting me closer to my destination.
The efficiency of public transportation can be counterintuitive.
Trains are really heavy. EVs don’t use energy while stopped.
The thing with trains and buses is that their weight swamps that of passengers, so even when running empty they use almost the same amount of energy. Think of all those LRT and subway trains running at night at 10% capacity. They still have the same braking losses at each station.
Lets look at some numbers from here:
From that we find the following average energy costs in terms of BTU per passenger mile:
These are the numbers everyone uses to claim that trains are more efficient than cars. But the ‘car’ number comes from the average fuel economy of today’s cars. If we want to compare fuel efficiency of cars to trains when new trains are online in a couple of decades, you have to use electric cars because supposedly that’s all that will be allowed by them. So how do electric cars compare?
Amtrack: 1,963 btu/pass mile
Tesla Model 3: 546 btu/pass mile
The numbers here are based on real-world measurements. The Tesla number is based on a average of 1.5 passengers, which is what the Department of Transportation says is average. The Amtrack number is the reported number given actual average capacity utilization of 23 passengers per vehicle.
Now, a completely full bus or train is really efficient. But public transportation does not run full all the time, which is why the btu/passenger mile range for trains actually in service can be from around 600 on extremely full routes to over 4,000.
But the worst a Tesla ever gets is 818 btu/passenger mile with one person. With four people, it’s about 205, which is lower than just about everything else.
In 20 years, taking a train will likely use more energy than just driving your electric car. Especially if we are expanding train service outside of the busy corridors they are currently in. Running trains on low utilization routes is a huge energy sink.
So… Today the average for trains is better than the average for cars. For buses it’s worse. But a full train or bus is MUCH better than a full car.
In an all-electric car world, the average car is better than the average train, a full train is still slightly better than an average car, but a full electric car kicks the ass of everything else in terms of passenger mile operational efficiency.
And we haven’t yet talked about the energy cost of building new train routes (lots and lots of concrete and steel - both extremely CO2 intensive), and the fact that the consumption of CO2 during construction is front-loaded, while whatever efficiency gains we get from trains, if any, won’t show up for a decade or two when they are finally running.
It would be a city with an amazingly capacious road network if all those passengers could simply ride in EVs instead of taking the train. People take the train because often there is no other practical way of making the journey that is their daily commute. In reality, a bumper to bumper slow crawl into a city centre is going to be very inefficient. Unless, of course, there was a way of evening out the demand on the roads by toll charging and a huge investment in parking spaces…and sympathetic employers willing to vary their employees hours to take account of road congestion.
These theoretical exercises are all very interesting, but they ignore the many other factors that influence the efficiency of public transport. Each city has its own legacy, of rivers, hills and a hundred years of existing infrastructure that are sunk assets. Not least demand for these daily commuter journeys in and out of town each day.
Is it sensible to assume that everyone is going to go back to the same journey pattern each day after the lockdowns and all the working from home? There are already signs that people are moving out of town.
Working from home or a local office for several days a week and using an EV for occasional journeys would be a much more pleasant prospect. I do worry about how the urban transport systems will adapt economically, if that becomes the trend. All those lost fares? Buses are, at least, very adaptable. Routes and frequency can be changed and knowing when the next bus is due from an app is very useful. There is a lot of scope for intelligent, adaptive scheduling that can greatly reduce buses running empty and improve efficiency. A flexible, urban transport system that adapts capacity according to consumer demand? I daresay the likes of Uber and Tesla are working on that…as long as someone fixes the roads.