All BRT systems are not created equal
Why BRT fleet size matters
A road is a scarce national asset - and a highly impactful one too. Road transport is an important enabler of economic activity. An efficient transit system with an extensive road network at its heart gives a country a competitive edge in moving people and goods economically1 Empirical evidence shows a strong correlation between road infrastructure and economic development. So, if we choose to restrict a section of a road to specific types of vehicles to improve mobility, we should have enough of those vehicles to ensure that the segregated road section is fully utilised.
Welcome to the 13th issue of 2 cents on a coin!
In my previous article, I broached the subject of dedicated bus lanes and concluded that an underutilised lane is worse than no dedicated lane. But the extent to which an underutilised BRT lane is worse than a free road network without dedicated lanes is nuanced - it depends on the level of utilisation of the bus lane compared to the general lane.
Buses have a significant edge over cars as a means of mass transit; 3 buses can do the job of 23 cars in moving people over 1 kilometre (both can move 115 people over that distance) so the worst-case scenario will be to dedicate a 1 kilometre lane to buses and have only 2 buses ply that lane since cars operating at full capacity will move more people over equal distance.
Although 3 buses can move 115 people over a kilometre and be on par with cars, that stretch of road will be underutilised with a fleet size so small especially if it is dedicated to buses alone. And underutilisation of the bus lane represents an opportunity for less congestion & traffic on the free lanes if more buses were made available to meet transit demand. In our 1km example, assuming latent demand, an optimal situation would be to use that dedicated lane up to capacity by supplying 25 (forty-seater) buses which can move up to a thousand people over 1 kilometre, leaving the general lane less congestion to that degree.
An underutilised bus lane represents an opportunity for less congestion & traffic on the free lanes if more buses were made available to meet transit demand.
So the focus for transport planners & operators of BRT lanes globally should be to have a fleet size no less than the number of buses which can carry an equivalent number of people as cars can, and optimally, to have a fleet size that will properly utilise the dedicated road space, all other factors considered (including current and projected transport demand) At the optimal fleet size, the commute time for all commuters along the entire corridor (both free & dedicated lanes) is the shortest. Beyond a certain point, if the fleet becomes surplus, congestion begins to build back up along the corridor.
How do global BRT systems stack up from this viewpoint?
We see interesting outcomes if we look at BRT systems in various cities - at least one from each region of the world.
East Asia & Pacific: Jakarta, Indonesia | The world’s longest BRT road network is in Jakarta, with a total BRT corridor length of over 250km. For this dedicated bus lane to operate at minimum efficiency, it should have a fleet size which can move up to 29,000 people - the number of people that 5-seater cars at full capacity can transport. At optimal efficiency, while operating 40-seater buses, the TransJakarta corridor can transport up to 417,000 and up to 2x this if the fleet size consists primarily of double-decker and bi-articulated buses. TransJakarta’s BRT currently has the capacity to move up to 113,000 passengers per trip along its corridor with a fleet comprising a mix of standard and articulated buses which can carry up to 120 passengers. At this level, the TransJakarta lane is 27% utilised.
East Asia & Pacific: Nagoya, Japan | In comparison to Jakarta, Nagoya’s Yurito line has a much smaller BRT corridor as the city’s transport infrastructure favours rail. Still, for a 7km corridor to be fully utilised with 40-seater buses, it should have enough of them to transport 11,300 passengers and at least 800. Nagoya’s fleet has the capacity to move 1,700 passengers per trip along its corridor, equivalent to 15% utilisation of the lane.
South Asia: Ahmedabad, India | Ahmedabad’s Janmarg corridor is 82km long with a minimum capacity of 9,000 passengers per trip (requiring 136 forty-seaters) and an optimal capacity of 136,000, equivalent to 2,061 forty-seaters.
The 136-bus fleet of this city’s BRT system is just at the minimum required. However, because the city uses larger capacity 80-passenger buses, Janmarg surpasses the minimum threshold and can transport up to 10,900 passengers per trip, or 8% of the lane’s capacity.
The Americas: Curitiba, Brazil | Of all the cities investigated, Curitiba’s Rede Integrada de Transporte is the only one with a fleet size & composition large enough to meet the BRT lane’s capacity. With its fleet of 1,226 buses, comprising various types of articulated buses, the BRT system can transport up to 143,000 people per trip, well above the minimum 9,000 required for the road network and greater than the 123,000 capacity that a fully 40-seater fleet would have afforded. A relevant further inquiry would be to investigate the impact of this fleet surplus on congestion in the city’s bus lanes.
Middle East and North Africa: Haifa, Israel | Isreal’s 3rd largest city, Haifa, is populated with close to a million inhabitants, and has a BRT lane of 40km. The city’s Matronit line consists of 90 articulated buses which can transport more than 11,000 people per trip, greater than the minimum 5,000 required for the special lane but only 18% of the capacity of the road network.
Eastern Europe and Central Asia: Istanbul, Turkey | Istanbul’s BRT lane can take up to 1,300 forty-seaters which could transport 86,000 people in one trip. Today, the city’s fleet of 350 185-seater buses can transport up to 64,000 people per trip which makes the road utilisation close to an optimal 75% utilisation.
Sub-Saharan Africa: Lagos, Nigeria | Lagos’ 22km BRT lane can transport up to 36,500 people in one trip. With its fleet size of 220 buses, the city’s BRT system for this Mile 12 → CMS route meets up to 40% of that capacity with the ability to carry 14,500 passengers per trip.
Western Europe: Oberhausen, Germany | The smallest of all the cities on the list, Oberhausen’s population is under 250,000 people. Having a similarly small BRT lane which can transport 11,600 people in one trip, the city’s BRT fleet size of 53 buses can utilise the lane up to 55%.
To wrap up, this exploration into the world of Bus Rapid Transit (BRT) systems has shed light on an essential factor often overlooked: the size of the BRT fleet. Roads are valuable resources driving economic growth, and efficient transit systems are key players in this journey. When we set aside lanes exclusively for buses, it's not enough to merely designate the space; we need a fleet large enough to truly make the most of it. When these lanes are underused, we miss out on an opportunity to ease traffic and congestion and to make the most of available road infrastructure to power economic activity. By looking at various cities around the globe, it's clear that the right fleet size matters. Some cities have figured this out – while others could benefit from bigger fleets to fully tap into the potential of these special lanes. The size of a BRT fleet isn't just a detail; it's a key ingredient in creating smoother, more efficient, and less congested urban transit systems for everyone.
Bus stops/stations are not considered in this article as factors which could truncate BRT road length
Standing capacity is considered (e.g. the capacity of the 40-seater bus totals 66)
BRT fleet size indicated is from various official sources and may exclude real-time fleet size e.g exclude data of defunct/retired vehicles which may not be updated in relevant databases.