Bus Rapid Transit and Light Rail – What is the Difference?

Depends what you are wanting to achieve

Light Rail or Bus Rapid Transit? The very question that can polarise even the most staunch urbanists in trying to create a better city and a better urban environment? But does it need to be this way?

NO it certainly does not. Light Rail or LRT and Bus Rapid Transit (BRT) are both very useful mass transit tools moving mass amounts of people from A to B (okay here come the A2B puns with Airport to Botany Rapid Transit) efficiently and without the need for large urban road ways. 

Both BRT and LRT are medium distance movers (so say up to 20km after which heavy rail becomes more viable for someone wanting to traverse the entire line such as Papakura to Britomart) and efficient at moving people short or those medium distances. In the end though what are the differences between the two?

The two differences is capacity (LRT moves more) and amenity (you can “green” LRT but can not with BRT) 

From The Transport Politic:

The Silly Argument Over BRT and Rail

Yonah Freemark.  May 25th, 2011 

» Reserving respect for each mode.

Both noted that BRT was cheaper to construct than rail lines. Each suggested that in an age of government pull backs and general skepticism over the value of public investment, BRT could offer substantial benefits to a transit system at a reasonable price. And each article concluded with a warning by rail proponents that buses wouldn’t be able to attract people out of their cars.

This is a sensationalized opposition between two modes of transportation that should be thought of as complementary. There are advantages to improved bus service in some corridors, reasons to support rail in others.

What is clear is that for the majority of American cities — excluding only a few in the Northeast — buses will remain the predominant mode of public transit for most riders, even after major expansions in train networks planned for cities from Charlotte to Phoenix. So even cities that choose to invest in rail projects must also spend on the improvement of their bus lines.

Nor is the difference in costs between rail lines and BRT nearly as great as some would argue. The Journal article quotes Dennis Hinebaugh, head of a transportation center at the University of South Florida, saying “You can build up to 10 BRT lines for the cost of one light-rail line.” That might be true if you’re comparing a train operating entirely in its own right-of-way with a bus running in a lane painted on the street. But a streetcar is probably cheaper than a busway. Just ask Hartford, whose busway project will cost $60 million a mile to build.


The Globe and Mail notes that “LRT advocates often argue that light rail has better interaction with the streetscape and is a better way of achieving dense, transit-oriented development than BRT,” and indeed, that point is frequently made. But plenty of vibrant neighborhoods in American cities have developed just fine without rail. The City of Seattle, whose first modern light rail line opened in 2009, nevertheless has been densifying for decades, increasing in population from 494,000 in 1980 to 609,000 in 2010 (with no annexation).

The best argument for rail is that it has the ability to provide massive rush-hour passenger-carrying capacity without destroying the city through which it runs. Whether buried in a subway or operating quietly along in grassy medians, trains can be integrated into the public realm without diminishing the pedestrian-friendly qualities all urbanists should hope to encourage. BRT boosters often argue that their mode of choice can carry a similar number of riders, but neglect to mention that this is only possible when buses arrive every 10 seconds along highway-like four-lane corridors. These are conditions that destroy the walking environment.

Fortunately for American cities looking to invest in new public transportation infrastructure, there are few places that demand the passenger-carrying capacity provided by those freeway-based BRT lines in places like Bogotá. In most metropolitan areas, a two-lane busway inserted on an arterial is perfectly appropriate and sometimes even beneficial for a city. 


Image above: BusWay in Nantes, France, from City of Nantes

Source: https://www.thetransportpolitic.com/2011/05/25/the-silly-argument-over-brt-and-rail/

North West Light Rail or even the Southern Airport Line Source: The Spinoff

Again in the end it comes down to capacity but more likely amenity. Light Rail can be easily “greened” with grass medians while Bus Rapid Transit is the same as a road – asphalt that incurs run off. So for a little bit of extra CAPEX (which was not much more between BRT and LRT) having a green Light Rail line allows for better urban amenity in the urban areas it runs through as well as better environmental benefits (run off). 

Source: @TransitSleuth
Graphic Impression of South Eastern Bus Way that would could also used for the Southern Airport Line

I have written on whether Airport to Botany (A2B) should be bus or light rail before: Should the Southern Airport Line be Light Rail or a Busway? In this case it came down to how the Airport terminus was built and where the depot for City Centre to Mangere Light Rail would be placed. If the depot was to be placed alongside State Highway 20B (land, industrial zoning and no residents near by) then having A2B as light rail became logical. 

In the end though it was the possibility of a green light rail line through Manukau that made LRT more attractive.  This is because the medians in Manukau and Te Irirangi Drive are already grass so why replace it with hard surface asphalt for busses? The answer is you wouldn’t – you keep as much green as possible. 

My earlier post on it:

We are doing the Airport Lines All Wrong Part 2: Where is South Auckland’s Green Line?

Written by Ben Ross – Talking Auckland

Why can’t South Auckland be green

When I have debates about the Southern Airport Line (Botany to Airport Rapid Transit via Manukau and Puhinui) with others the debate is usually around economics (cost and capacity) and basic environmental stuff (capacity and cars off the road). What I forget (and naughty me in being a Geographer as well) was the deeper environmental impacts between a bus way and a light rail line – that is surface run off of storm water and the possibility of carbon sinks.

A busway is basically asphalt from beginning to end – so hard run off. Yes in New Zealand we do storm water gardens for hard surface run off before that said storm water hits the waterways but is that an appropriate response for an existing urban area like Southern Auckland?

Lagoon Drive with proposed bus-way
Source: http://ourauckland.aucklandcouncil.govt.nz/articles/news/2016/04/busway-for-east-auckland-a-step-closer/

Light Rail goes further in that the right of way is already green with the only hard surface being the tracks themselves (the sleeps would be under the soil surface). This means each time it rains the storm water is already collected by the green right-of-way, filter and finally peculated before hitting the waterway systems. No need for storm water ponds and flooding also becomes mitigated as well unlike what we would get with bus rapid transit (BRT). Also green is just nicer to look at than grey asphalt especially in an urban area.

These tweets from Transit Sleuth illustrate green transit:

So my question is this?

If the Isthmus (Central Auckland) is to get Light Rail for the Northern Airport Line and no doubt a green LRT line at that (Dominion Road) then why does Southern Auckland get stuck with a noisy bus rapid transit system that has consequences of amplified noise (bus, and asphalt reflecting the noise) and mass storm water run off from the asphalt?

As it was pointed out to me Southern Auckland also houses four of the five heavy industrial complexes meaning hard surface area is higher – thus run off is higher. The Southern Airport Line runs through two of the complexes so adding some green would mitigate that run off. A green transit line for the SAirL would also act as a carbon sink for the industrial South as well rather than as a carbon emitter as we would otherwise get if the line was BRT.

Also is Southern Auckland not allowed a green transit line like the Isthmus is – especially as the Southern Airport Line if your first transit line you catch heading to either the City Centre or south of Auckland?

I personally think that it is a bit stink the Isthmus gets a green transit line than the more populous South. Just because we have industry and social deprivation does not mean we can not have a green transit line either.

Noise reduction, storm water absorbent, carbon sink, amenity provider – this is what a green transit line would provide compared to the sea of asphalt a bus way would give in an otherwise highly built up area.

As for cost? Yes Light Rail costs more than Busways in pure dollar terms but in full social and environmental terms green LRT wins out. Especially when the Line traverses industrial areas or highly built up areas like a large Metropolitan Centre such as Manukau.

The Southern Airport Line through Manukau City Centre. Black – Heavy Rail, Blue = busses, Grey = possible LLRT route

Would Light Rail to Botany cost more? Yes, does it offer more benefits such as green amenities owing to Manukau’s grass medians? Yes. Would a green light rail line better blend in to the urban environment or more asphalt (something South Auckland does not need)? I’ll take green please any day of the week. Run off mitigated? Give me again a green LRT line any day! 

It is more than bums on seats (given A2B is going to end up busy anyway especially as two Metropolitan Centres are linked up, something City Centre to Mangere will not have), it is about wider amenity – GREEN amenity!