Here’s a good reason for moving to public transport: we are not going to significantly reduce traffic congestion anytime soon by using improved traffic modelling and management methods.
Building new roads is not the solution either. The Wall Street online quotes Martin Wachs, director of RAND Corp’s transportation, space, and technology programme, as saying that new roads lead to more travel (traffic) due to an effect known as ‘triple convergence’: if new roads are built, many drivers who had shifted their trips 1) to off-peak hours, or 2) to different roads, or 3) to public transport, would resume their previous pattern and converge onto the new highway. See Wall Street article here. Another reason to move away from private vehicles is to reduce fuel emissions that contribute to global warming and to conserve rapidly depleting fossil fuels and natural gas reserves.