Back in 1986, I was a student at the London School of Economics. When I would ride the Tube, I would marvel that the brilliant Brits had figured out how to have displays indicating how many minutes until the next train would appear. Given that I grew up in New York City with its 1912 Subway system and antiquated 1912 technology, I was not used to actually being able to predict when a train would appear. Waiting for buses and subways represents a significant fixed time cost that raises the time required for commuting and thus the full cost (which reflects time and out of pocket $ for the fare) of taking public transit. This encourages using cars with the resulting congestion and pollution externalities.
New information technology has solved this problem. The NY Times reports that public transit users with smart phones will have real time information about what bus routes go where and how long they will have to wait for a bus to show up to their closest bus stop. When I was in Singapore this summer, I saw this process at work and it was a perfect substitute for a taxi ride (we couldn't find a taxi). In this sense, information technology will help low carbon buses to compete for urban ridership with taxis and private cars and this will improve the finances for buses (which will be closer to 100% capacity) and will save people time and reduce GHG and local emissions.