Ahmedabad takes the bus

With crumbling transport infrastructure in many of our cities, various solutions to tackle this are being proposed around the country, and huge investments are in the pipeline. Interestingly, while the attention of nearly every other metropolitan area seems fixed on rail-based systems (Metros) as the solution, Ahmedabad has taken a different route, placing its faith in bus rapid transport. The merit of this alternative is worth examining, as in the coming years many other cities will travel down the congested paths that the major metropolitan areas already find themselves in.

Bus Rapid Transit (BRT) takes part of its name from "Rapid Transit", which describes a high-capacity transport system with its own right-of-way, implemented using buses through infrastructural and scheduling improvements, to provide a high level of service. Complicated as it sounds, this is nothing but high-capacity articulated buses operating in lanes reserved for their exclusive use.

Segregation - the first step

Would dedicated lanes for buses mean sub-optimal use of already over-capacity roadways? No. Segregation by vehicle type or travel mode is the key to improving traffic flow. Flow theorists studying transport always emphasize homogeneity. On a typical arterial road, buses account for about 10% of the total traffic, but can occupy twice that percentage of road space in terms of area. Given that there is a bus stop every 1.5 to 2 kilometres, imagine the road space consumed by the least manoeuvrable traffic, that is additionally changing lanes back and forth regularly. To add to the problem, buses typically stop 5-7 feet away from the kerb in many locations; this space around the bus stop is anyway eliminated from use due the overflow of passengers waiting at the bus station. In a BRT system the median and the inner most lane or the left most lane can be dedicated to the bus. In case of median lanes bus stops or stations can be built in the median to further improve the flow. Passengers are allowed to cross at the nearest signal or intersections.

A bust stop in Curitiba, Brazil, home to one of the most successful BRT systems in the world. (Picture source: Wikipedia)

It might seem criminal to eliminate one lane of traffic for buses. However, experiences from around the globe, contrary to expectation, tell us that in fact BRT systems have improved traffic flow in the non-BRT lanes too. The segregation of traffic is one of the big reasons for this. A well implemented efficiently-run BRTS will also cause citizens to switch travel modes from car to bus, which will further alleviate the traffic situation.

Planning road volumes

In India, roads are often designed to take a particular number of users, say 30,000 persons per hour per direction. But the demand for use of any one road tells us only part of the story; looking at corridor volumes using a travel demand model is a flawed approach. It is like designing for 30,000 people to travel from A and B, not from their home to work or education institution and vice versa. Travel Demand does not work like that, it exists between origins and destinations, not along point A and point B on an arterial. Hence a service which delivers passengers from their desired origins to their desired destinations should be concieved while designing roadways.

At the same time existing BRTS, like the Trans Millenio in the Colombian capital Bogota, claim to carry 40,000 passengers per hour per direction. A certain degree of infrastructural and design innovation is required to achieve this goal, but it has been proved possible. A single dedicated lane BRTS is known to carry 20,000 passengers per hour per direction. A second lane at bus stops for overtaking has shown to double the system capacity.

And at what cost?

If dedicated bus lanes are so efficient, should we be choosing these instead of Metros for the big cities? Is a 30-km Metro really better than a 500-km BRTS? A comparison between the Delhi Metro and Ahmedabad's BRT project is instructive.

The first phase of the Delhi metro is 64 kms. The capital cost of Phase I was estimated as Rs.6000 crores at Apr 1996 price levels. However, taking into account the cost escalation during the construction period of nearly eight years, the completion cost was Rs.10,571 crores. That's a whopping Rs.165 crores per km. The Bangalore metro project, which recently got off the ground, will be similar in cost; its projected cost of Rs.6500 crores at today's price levels works out to Rs.178 crores per km, even without accounting for the cost escalation. Almost certainly, the completed cost will be higher.

The Ahmedabad BRT project comprises of creating a 150-km long two-way corridor for swanky 70-seat buses; existing circular roads and some arterial roads will be widened for these to ply, and encroachments from certain portions will be removed. The first tender issued is for the 10-km stretch of road between Naroda and Thakkar Bapanagar in phase-I, at a cost of Rs 75-crore, to be completed in 18-24 months after the bid is finalised. That's a mere 7.5 crores a km, a tenth of the costs for a Metro. A second tender will be issued for another 8-km Naroda-Chiloda stretch next month, also as part of phase-I.

Higher costs for Metros may be acceptable, if they are accompanied by substantially higher benefits to the transport infrastructure's current woes. But look at how Delhi's Metro is functioning. The expected ridership in 2005 was 15 lakh passenger trips per day. Today, after more than a year of being in service, the system actually gets about 4.5 lakh passengers a day. It is very easy to blame the travel demand forecasting model for incorrectly forecasting ridership. How can these be so different? One explanation is the lack of connectivity at ends of the metro lines. This is very similar to the 'A to B' example cited above.

Flexibility - another reason for BRTS

An important advantage of BRTS is its flexibility. Like in Ahmedabad, the system can first be implemented over a 10 km stretch. This first-phase system should be in operation in less than 2 years. This approach lends itself to incremental learning of the problem, and eliminating mistakes as the development proceeds. The relatively low implementation costs also don't leave taxpayers tied to one particular technology or solution. And at the operational level, design changes in response to new concerns are also relatively simple to make even after the system is under operation. A fixed-line Metro at high cost offers none of this flexibility.

A number of other advantages too can accrue from BRTS, but these greatly depend upon design, as well as adaptation of design to local conditions and implementation. Even without those, however, it is quite likely that bus rapid transit is the more profitable solution for many cities. It is very encouraging though to see Ahmedabad make the bold decision to go with BRTS, against the conventional wisdom that favours Metros. As many as 35 cities in the world have successful BRTS, including five in China, besides North and Latin America and Europe. One successful implementation in Ahmedabad could lead to a windfall of equitable, sustainable, affordable and environment-friendly BRTS projects across the country.