21 April 2017

Move together

What do Beijing, Buenos Aires, Istanbul, Mexico City and Islamabad have in common? One of the correct answers is: fantastic food! Another one is: a specific bus system, called BRT, for Bus Rapid Transit!

Physically dedicated road lanes, high-capacity buses

“A BRT includes road lanes which are dedicated to the buses”, Carlos says. “The system also includes boarding stations, high-capacity vehicles and automated fare collection.” Carlos Mojica is an expert in public transportation who works for the Inter-American Development Bank (IDB). He knows the Transmilenio system very well. Transmilenio is the BRT system of the city of Bogota, the capital of Colombia. He explains: “The IDB finances projects and provides technical support to governments of Latin American and the Caribbean to improve health, education and infrastructure including transportation.”

This is Transmilenio, the Bogota BRT! Most of the time the BRT roadways have physical separation which means cars cannot access the lines at all. On one same line, the bus number 1 may not stop at the same stations than the bus number 2.

Carlos says: “BRT systems mimic the experience of fixed guided systems such as metros. Indeed the bus system combines the large capacity and high speed of a metro. Transmilenio started in 2000; it ensures today 2.2 million trips every day!” As of end of 2016, about 34 million people use BRT worldwide every day. Latin America has the most cities with BRT systems (69 cities). 

"Public transportation also contributes to solve other issues like road safety and public health"

Carlos explains that “a city gets disconnected when local authorities do not develop public transportation. Communities get separated by the car highways and the distances. This is the case of US large cities for instance. Accident rate is high on these highways. In the US, 40 thousand people die every year on the roads. We believe cities should invest in efficient public transportation. More people using public transportation will not only improve mobility but will also contribute to solve other issues like road safety and public health.”

One Climate One Challenge Meza Gheung Bogota BRT Bus Rapid Transit Transmilenio Emissions Transport Transportation Bus Car Tram Tramway Metro Kg CO2 eq passenger kilometer km
Here is Carlos! Yes, Frédéric has a model of
Transmilenio bus in his hands!
In several emerging countries, cities cannot afford building a metro. It is too expensive. BRT system is a very good option. Carlos says: “It provides lower cost and flexibility. And it is quicker to implement. Transmilenio is successful. An indicator of this success is that the system was replicated all around the world, in more than 100 cities! Bogota was a pioneer. It was the first large city in the world to switch to a full BRT. Today China, Indonesia, Vietnam and many others are implementing BRT systems.

The Transmilenio system has allowed decreasing the total number of buses in the streets of Bogota from 21 thousand buses to around 12 thousand. This achievement has greatly reduced pollution in the city. On the other side, Transmilenio faces a problem of over-occupancy at certain periods of the day.

The city has started to introduce hybrid buses. Bogota has the biggest fleet of hybrid buses in Latin America, with 300 buses!” Carlos concludes: “You know, low-emission engine technology is a good thing however it is also important to optimize the network in order to ensure the buses are occupied. Occupancy is key!”

Public better than electric

Engine technology, vehicle occupancy. We wanted to learn more. This is why we met with Luis! Luis Belalcazar is a researcher in “Transport and air quality”. He works for the National University (Universidad Nacional), in Bogota.

One Climate One Challenge Meza Gheung Bogota BRT Bus Rapid Transit Transmilenio Emissions Transport Transportation Bus Car Tram Tramway Metro Kg CO2 eq passenger kilometer km
We met Luis at the Universidad Nacional
of Bogota.
He says, “In Bogota, 80% of the air pollution comes from transportation. The rest of the emissions come from the industry. In March my team released a study which took us 5 years of work. In particular, it compares the transportation options in terms of greenhouse gas emissions and other pollutants. It takes into account the life cycle assessment of the transport: operation but also the fuel sourcing and production. Well to wheels data. We performed the study within the Colombian context: the electricity here is quite low-carbon electricity since 70% of it comes from hydro dams.

One conclusion of the study is the following: 1 person alone in an electric car emits more than 1 person in a fully-occupied diesel bus! Globally speaking, the study shows that the bus option is preferable, even if the bus is diesel-powered.” Better to use a public bus than an electric car! “Tramway systems and metro systems also emit less,” Luis says. “In an update of the study, the impact of the vehicle manufacturing will be integrated. It will further promote public transportation.”

He adds: “Our bus occupancy must improve. It is very important a bus does not go empty. Also a next step for Bogota Transmilenio would be to get more hybrid or gas buses. Gas is much better than standard gasoline or diesel. Its combustion releases less carbon, and it releases much less particles which are dangerous for the health.” Better for the health, better for the climate, let’s take this bus or this tramway!

Range of emissions per Kilometer, per passenger. Extract from Luis’s study. ©Cuellar et al.
The data does not include the construction of the vehicles. The buses are considered fully occupied (right side of the bar) or with 25% over-occupancy (left side). The cars are considered to go with the driver only, which is common in a daily use (right side of the bar), or full occupancy (left side).
Luis says: “Electric buses are a very good option. The figures for metro and tramway systems should be lower than diesel bus.”
A study, by Carbone 4 and Alstom, says that a tramway system emits about 50 percent less than a diesel BRT system (whole lifecycle including construction and operation).