Intermediate 
We may not yet be living in an age of  ying cars, as predicted in the 1985  lm Back to the Future II, but the rise of smartphones and other new technologies is creating a reality that is just as exciting and almost as far-fetched. Experts agree that economic and demographic changes, technological advances, and environmental concerns are fundamentally changing transportation. Its a very dynamic time, said transport expert Robert Puentes. Theres a tighter connection between transportation and the economic health of cities and its impact on people.
As the transport infrastructure grows old, cities across the US are forced to rede ne what transportation is. Urban planners, transportation experts and scientists are now realizing that old methods focused on reducing traf c congestion arent enough to solve problems like population growth and carbon emissions, and transportation is now a key part of protecting the environment.
Big US cities like Los Angeles and Chicago are working to make better use of their streets by adding more bus lanes and pedestrian walkways, and expanding rail networks. At the same time, they are working on advanced technologies that will allow a vehicle to drive itself and communicate with other vehicles and its environment. The most sustainable places to live are places that have multi-modal transport systems, Puentes said
Here are three key ideas that experts predict will in uence transportation in the coming years.
Connectivity Ride-sharing services like Uber  taxis booked via smartphone  and apps like Waze, which uses real-time traf c data to  nd the quickest routes for drivers, are dramatically changing how people move around and affecting the way traf c moves through a city. Communication between riders and drivers, between different vehicles and between cars and infrastructure is bringing transportation into a new era, according to Allan Clelland, an expert on transportation technology.
According to a recent study, car travel has reduced among people born in the 1990s compared to previous generations. According to the study, people born in the 1990s are making 4% fewer car trips and travelling 18% fewer miles per year, on average, than members of previous generations did at the same stage in their lives.
People still driving cars are dealing with less traf c thanks to Waze. Experts say the traf c app has reduced congestion on motorways and reduced travel times for drivers. But it has also led to a problematic rise in cars moving through residential neighbourhoods.
This trend could continue as vehicle-to-vehicle data communication, as well as communication between vehicles and the surrounding infrastructure, grows. Currently, a traf c light knows when a car is getting close but thats all. Companies are working to develop technology that will allow a vehicle to tell traf c control systems not only that it is present but also where it is going and how fast it is travelling.
Automation Driverless cars have been in the headlines ever since Google began road testing the vehicles back in 2012 but no-one really knows when driverless cars will become commonplace. However, the partial automation of cars is already underway. Automation will probably happen in stages:  rst, there might be automated buses with their own lanes, then perhaps lorries in ports or mining towns: that is, vehicles that are connected electronically and travel in single  le.
The idea of a fully automated transportation system is intriguing because it could improve safety by removing human error. It could also help reduce carbon emissions and traf c congestion, and allow more people access to cars. But, even if driverless technology were ready to use now, it would take a long time to get fully automated because the average age of cars on the road is 11.5 years old.
To see what driverless cars might look like in action, go to the video at: vimeo.com/37751380.
Environmental concern As the world races to avoid catastrophic climate change and countries and cities work to meet ambitious emissions goals, these policies could also have a big effect on the future of transportation. Concern about the environment could lead to everything from zero- and low-emission vehicles to apps that encourage more walking, biking and carpooling.
When considering the future of transportation, its also important to keep in mind why people travel: they may be going to work, to meet friends or family, or to do the shopping. Technologies that reduce the need for those trips  for example, virtual meetings or telecommuting  could also have a big effect on transportation.
In the past, the idea of a  ying car represented the best in innovation but the technologies that people are imagining and developing now are possibly even more sophisticated  and more useful in solving the social and environmental problems that we face in the coming decades.