n. Informal One who avoids paying the fare for public transportation, especially the subway. American Heritage® Dictionary
noun A person who illegally avoids paying a fare, as by entering a public bus through the exit door. Random House
fare evasion or ticket evasion is the act of travelling on public transport in disregard of the law and/or regulation, having deliberately not purchased the required ticket to travel (having had the chance to do so.) Wikipedia
As I am almost certainly the only person on this board who has ever arrested anyone for this activity, I can tell you with absolute certainty that in New York City, the legal term that the State of New York uses in the statute that describes this criminal offense is theft of services. The formal, but not the legal, term for the action (such as might be used in the press, or in a news release issued by the Transit Authority) is fare evasion, and a person who does not pay his required fare is a fare evader. The popular term universally used by police is "farebeating", while a person who "beats the fare" is a "farebeater." [...] I would consider "fare dodger" to be something those unfamiliar with the term might not immediately understand.
GreenWhiteBlue, January 14, 2009 - WordReference (emphasis is mine.)
Slang A person who attends a performance, sports event, etc., or travels on a train, airplane, etc., without having paid for a ticket, especially a person using a complimentary ticket or free pass. Random House
One who has not paid for a ticket M-W