text: Tuesday's Amtrak crash raises concerns about transportation safety.
  But statistically speaking, trains are actually a very safe way to travel -- much safer than driving.
  CNNMoney calculated how many people are killed for every one billion passenger miles traveled to compare the safety of different modes of transportation. So a 500-mile trip on a plane carrying 100 people would be equivalent in passenger miles to someone driving a 500 mile car trip alone 100 times.
  The figures are for U.S travel only using data for the most recent five-year period that's available.
  Motorcycles: Motorcycles are far more dangerous than most forms of transportation, but what's surprising is just how much more dangerous they are. There were 23,000 people killed by them over a five year period, making them by far a traveler's most dangerous option.
  Cars & trucks: More than 113,000 people were killed riding in cars or trucks in the five years ending in 2013, which is a much higher absolute number than any other form of transportation. But that's because people most often travel in cars and trucks.
  Commuter rails & Amtrak: Amtrak and commuter railroads are a relatively safe mode of travel, with only a handful of deaths each year from 2009 through 2013.
  But since then there have been a number of major accidents, including two commuter rail accidents in the New York area last fall and earlier this year, as well as Tuesday's Amtrak crash.
  Subways & metro rail: These trains, which include subways and light rail systems, carry passengers for even more miles than Amtrak and commuter rail lines combined. And their safety record is fairly good.
  The last major accident involved the Washington DC Red Line, which had an accident in 2009 that killed the train's operator and eight passengers.
  Buses: They're one of the safest forms of travel around. School buses, which generally drive slowly on local streets and are painted a bright yellow to alert other drivers, are a a big reason for that. City buses also provide very safe transportation.
  Commercial airlines: Nothing is safer than a U.S. commercial planes, which have been involved in very few crashes. The 2013 Asiana Airlines crash in San Francisco, which killed three passengers, is not included in these statistics since that was a foreign carrier on U.S. soil.
  Small planes, known as air taxis, that carry passengers to very rural destinations are responsible for most of the deaths in this category. Private planes cause far more deaths than commercial airlines, but those deaths also are not included in these figures.