When Electric Buses Make Sense, & When They Just Don’t

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In a previous article, I mentioned Albuquerque Rapid Transit (ART), a Bus Rapid Transit (BRT) system that went in a few years ago in the city. Like many, I was disappointed that they replaced some allegedly problematic electric buses they had purchased from BYD with “clean diesel” articulated buses. Working out their issues with BYD or switching to another manufacturer of electric bus seemed like the right way to handle that, and going to diesel…not so much.

What I didn’t realize at the time was that electric buses aren’t always the best answer for public transit. Yes, electric buses are definitely better than a diesel or natural gas bus. That’s indisputable without seriously bending the facts. The thing is, combustion buses aren’t the only competition electric buses have, and in many situations, even cleaner options are the answer.

Ways Light Rail Is Better Than An Electric Bus (In Some Situations)

What’s an even better option? Light rail. This video explores many of the reasons why a light rail system is usually better than BRT.

The biggest advantage to using rail is that you’re not facing the rolling resistance a vehicle with tires faces. Pushing squishy and partially slippery tires around takes a lot more energy than “steel-on-steel” rail vehicles. There’s almost zero deformation, and no real slippage, so light rail takes a lot less electricity than an electric bus to move.

Maintenance isn’t as big a deal with an electric bus, so light rail doesn’t beat them as much in this regard. But, over time, the cost of replacing a battery pack is something that a light rail system just doesn’t have to deal with. Because they get their electricity from overhead wires or an electrified third rail, most light rail systems don’t need a big bank of batteries. The few that do tend to use the batteries for regenerative braking or to keep rolling for short sections where electricity won’t be available, but in those cases the batteries will be much smaller and easier to replace when the time comes.

Light rail systems are also very flexible when it comes to capacity. If there gets to be too many people on a route, the only option is to add more buses, and with those buses the full cost of each additional bus that runs on the line. The light rail just adds another section of train to the vehicle, and the capacity of the vehicle overall can be changed seasonally or even hourly to best match ridership.

Cost is the big area where an electric bus and light rail can be competitive. The cost of laying down rail, building stations, and running wires or third rails, and everything else makes light rail a lot more infrastructure heavy compared to a bus. The bus can basically just hit the road, and drive where everyone else drives, so the up front costs are a lot lower.

The Big Decider: How Train-Like Is The Route?

Routes like Albuquerque’s BRT system illustrate how the decision to go with rail or bus hinges on this question. ART has dedicated lanes, stations with bus-level platforms to speed loading and unloading of passengers, and other features that basically makes it like a train on tires. Sure, it rides on pavement, but it’s different enough that they have to create PSAs showing an armed agent of the state telling you to not drive where it drives, or face the risk of ticketing or accidents.

This is a perfect example of a situation where light rail would make more sense, It’s a fixed route with lots of infrastructure, just like a train. The upfront costs would be a little higher, as you’d want to keep cars completely off the tracks between intersections (like ART honestly should have done), but the cost of platforms is something that is common to BRT and light rail. Plus, the maintenance of diesel buses is going to be far more expensive over time than the cost of laying rail and wires would have cost for this fixed route.

Streetcars, trolleys, and other smaller rail systems don’t require platforms or dedicated lanes in most cases, so rail is also a better option for fixed routes without that infrastructure. They don’t share all of the advantages of light rail because you can’t just add more cars to the train, but they don’t have rolling resistance or big battery packs.

Where rail doesn’t make sense is when routes aren’t fixed. Some cities need the extra flexibility of a wheeled vehicle that can drive on any traffic lane, as they can change routes quickly with only signage changes. Or, more often, needs can differ in some cities seasonally or even daily. Places like a college town might reduce or completely eliminate parts of a route on different parts of a year, and then adopt new routes once the summer is over.

Thus, the more fixed a route is, the more rail is the answer. The less fixed and more flexible a transit system must be, the more an electric bus becomes the clear winner, despite the costs, because laying down new rail all the time and tearing it back up makes no sense at all. This means that BRT systems like ART make no sense at all, because they are so train-like that they might as well just be a train.

What Makes Even Less Sense

In this article, I only explored when an electric bus or an electric light rail or trolley system might make more sense. What I didn’t explore was how diesel buses fit into this chart.

The answer? They just don’t fit anywhere on the chart in 2021, and haven’t fit since 2015 or so. Cities that purchase combustion buses are getting basically the worst of all worlds with their tax dollars. They’re getting the least efficient vehicle with the least efficient engine, with the highest maintenance costs. These quickly outstrip the costs of electric systems of any kind.

Whether a city adopts electric buses or light rail doesn’t matter as much as keeping them from being stupid and buying combustion vehicles for public transportation today.

Featured image: Screenshot from one of the YouTube videos embedded in this article.