With international oil prices topping 51 dollars a barrel, more and more citizens are turning to public transportation instead of driving their cars.

BC Card Company said Wednesday that after surveying some 5.6 million users of transportation cards, card usage for last month was found to have risen more than 20 percent compared to the beginning of this year. Seoul and Incheon witnessed the biggest growth - 17 percent - in the usage of the transportation cards.

Earlier on Tuesday, oil prices topped 51 dollars a barrel as output in the Gulf of Mexico continued to remain in shambles more than two weeks after Hurricane Ivan tore through the region.

Light crude for November delivery soared 1.18 dollars to settle at 51.09 dollars a barrel Tuesday on the New York Mercantile Exchange — the highest level in the exchange's history.