MIAMI -- Skyrocketing gas prices have some South Florida drivers hanging up the car keys and giving public transportation a try.

Miami-Dade Transit officials said ridership increased 1.5 percent in January, and they expect even larger increases as prices at the pump have continued to climb.

The new riders, according to Miami-Dade Transit's Manuel Palmiero, are "people that are on the fence, that will take transit once they get to the point that prices are $4 or $4.25 and it's just not worth it."

The jump in ridership mirrors a national trend. The American Public Transportation Association recently released figures for 2007, showing ridership of public transportation setting a 50-year high: 10.3 billion rides, an increase of 2.1 percent from 2006.

"In light of high gas prices, increased road congestion and expanded public transit services, this continued growth in ridership demonstrates how important public transportation is for America," said APTA President William W. Millar. "Now, with gas prices predicted to rise to $4 a gallon, there is a greater urgency for higher federal funding to expand U.S. public transportation systems so Americans have an affordable transportation choice."

In Miami-Dade County, new metrobus riders include Erix Mercedes, a student who recently stopped driving to school when gas prices neared $4 a gallon.

"I can't afford it," Mercedes told Local 10's Mark Joyella. "I can't afford gas."