According to a recent online travel service survey, London has the best public transportation system in the world — and the most overpriced. TripAdvisor.com surveyed more than 2,000 travelers globally to find out what they deemed the "best" and the "worst." New York City was recognized as having the best public transportation system in the U.S., and second worldwide. Washington, D.C., has the cleanest and safest public transit, according to the panel of travelers, while Los Angeles has the worst public transportation system. Nearly three-quarters of survey respondents said a city's public transportation system is a travel consideration. Fourteen-percent of travelers said that the recent rise in fuel prices has inspired them to use public transportation more often, while 9% said they avoid using public transportation because of concerns about terrorism. Top five public transportation systems in the world: 1. London
2. New York City
3. Paris
4. Washington, D.C.
5. Hong Kong