What is the main way of transportation in the world?

Can a felon in pa drive a school bus? What kind of train was the first train? How far is worcester to London by train? When did the first transcontinental railroad begin operation? Where is the train station in bern Switzerland? What does where warm waters halt mean? What time is the last train from Nottingham to Heathrow airport? Does the Long Island Railroad sell multiple ride passes? How did the incas get from one place to another? What did the NYC subway cost in 1999? Are there more occupational accidents then traffic accidents? What does the word Pinhead mean in railroad slang? When start construction on Birmingham Northern Beltline? What are good uses of a mobility scooter? How long did it take to build the first train? How did people travel before railways? What does US DOT means in transportation? Who invented air brakes for trains? What are the train price from Venice to Florence? Why it is dangerous to stand near fast moving train?