Seattle Transit Blog

Buses are often hailed as the cheaper solution for mass transit. I think there are fundamental flaws in most of the comparisons we see between BRT and rail systems, and that it’s unlikely mainline buses actually make sense in long term planning.

When I say mainline, I mean corridors that will have long term need for transportation. I think Martin’s brought up some great points about what that means – I don’t, for instance, think that we need to build past Redmond at this point, or past Issaquah – we don’t know what is going to happen there in the coming decades, and we don’t have the money to guess. We have some clear centers that are not going to disappear – some are already walkable and dense, like some of Seattle’s neighborhoods, and some are car-centered today, with lots of parking and one-story clusters of development, but ripe for reconstruction to funnel the new growth coming to our region. There’s no “flexibility” argument here, though – urban corridors don’t pack up and move, they never have and they never will. This isn’t a frontier town, this is a major city.

I’m sitting on a bus right now, in stop and go traffic at 9th and Stewart in downtown – so I want to start with the fallacy that building HOV lanes on our freeways is somehow equivalent to building new rail right of way. I think to some, especially to those who use transit already, it’s clear that these are nowhere near the same levels of service. If I head downtown from work, like today, about half of my commute is spent in downtown traffic – a tiny percentage of the overall distance. No matter what we do to SR-520, the 15-20 minutes I spend getting from one end of downtown to the other will not be affected. In order to provide consistent service end to end, we have to build new right of way end to end.

That right of way costs money – lots of money. With a project like University Link, in order to get anything like three minute service from Husky Stadium to the center of Capitol Hill, you’d have to tunnel for buses just as we are for rail. The cost of laying rails in that tunnel is tiny compared to the tunnel itself. You can look at any segment of our light rail system and make similar observations – in the Rainier Valley, we repaved the entire roadway to make space not for trains, per se, but for dedicated right of way. The cost is due mostly to the level of service, not the technology, but that level of service difference is what creates the consistency and reliability that we value in rail systems. When you actually compare the capital cost of a BRT system that provides the same level of service as a light rail system, you find that your right of way costs are exactly the same.

So, you say, you’ve seen capital cost comparisons that meet these requirements, have exactly the same amount of new right of way, but still show BRT being cheaper? Unless they’re in totally different cities or countries with different labor costs and safety requirements, they’re almost always missing one thing – electrification. In this area especially, that’s a big deal. While the cost of oil has doubled in the last couple of years, the cost of our electricity hasn’t. Electrification insulates us from $4.50 per gallon diesel – or $6, or $10. We’re designing a system to last not decades, but hundreds of years – we can’t just shut it down to change over later. But when you electrify, your total cost of construction for rail versus bus is nearly identical – which makes sense, because it’s not any cheaper to lay concrete roadway than to lay rail, and all of your other infrastructure is a product of the level of service, not the technology.

Okay, so what’s the problem? Why are you so hell-bent on building rail if they’re exactly the same, Ben? Two reasons:

First, capacity. Some BRT advocates will tell you that buses can have exactly the same capacity as rail. They’re either uninformed, or they’re lying. Even with double-articulated coaches as in Curitiba, you’re looking at an 85 foot long vehicle with 57 seats. Curitiba claims they can reach 270 passengers – but at the measure of 6 passengers per square meter standing. With half that standing density, 3 passengers per square meter, our light rail cars carry 200 (with 74 seated). If you went by Curitiba standards, we’d carry more than 325 people per car. These cost about the same amount to operate and maintain – for the sake of discussion, about half the operations cost of a vehicle like this is the fuel, and about half the operator, although that now varies a lot more with the high cost of fuel prices, so my comparison gives buses a slight advantage.

But wait – we can tack three more vehicles onto a Link train behind the same operator. If we want to add another bus, that means paying another operator, so Link scales to four car trains at some 5/8 the cost – and a full metro can go much higher, with as many as 12 cars. We can also go down to lower headways than the buses can without affecting service quality – the big limiter is the time taken to board, which is a lot lower for four simultaneous light rail cars than four sequential buses, even when the buses have multiple doors. Rail can also offer a very finely tuned interface between vehicle and platform – on new systems, no ramps or lifts are necessary for wheelchair users.

I’ve already touched on it a bit, but the last reason is long-term cost. A rail vehicle costs more than a bus, but lasts at least proportionally longer – New York City has subway cars well over 50 years old in service today, and recently retired some that were even older. Most buses last ten years, some fifteen. Our Breda coaches in Seattle are now nearly 20 – but that has only been possible after major overhauls. They are nearing the end of their service lives. At the same time, fuel costs for our bus system have doubled, while our electricity prices in the city (I don’t know about you Puget Sound Energy folks) have stayed basically the same.

With any dedicated right of way, ridership is generated largely by the existence of the transportation system. I suspect that this would be the case for true BRT as well, because the factors that generate that ridership have to do more with the pedestrian density generated around stations than with the mode. In the long term I think the immediate space around any system built in any of the Puget Sound urban corridors today will increase in density to the point where the capacity offered by a rail system is absolutely necessary. I think our recent exercise at Reality Check helped make it clear that most of our regional leaders are on the same page in that respect.

Buses are great feeders, but they have no place as a mainline corridor – claims of cost savings are not for equivalent systems and don’t hold up in the long term. If you’re going to build a real transit system, make it rail and do it right.