DOWNERS GROVE, Ill. (CBS) — New figures show fewer drivers than expected have abandoned the Illinois toll roads since the fees nearly doubled.

As WBBM Newsradio’s Regine Schlesinger reports, the Illinois Toll Highway Authority expected to lose about 6 percent of drivers after the toll increase went into effect on Jan. 1.

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LISTEN: WBBM Newsradio’s Regine Schlesinger reports

But now, the agency reports the system experienced only a 2.4 percent drop in car traffic for the first three months of this year, according to the Daily Herald.

The newspaper quotes tollway executive director Kristi LaFleur as saying the authority has performed better than anticipated.

Meanwhile, more truckers drove the toll roads during the first quarter – a nearly 7 percent jump, the Daily Herald reported. Truck tolls don’t go up until 2015.

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Because of the higher tolls, the system has increased revenue to $224 million, compared to the $157 million the tollway took in during the same period last year.

As of Jan.1, the 40-cent basic rate toll for I-Pass users – unchanged since 1983 – went up to 75 cents. Drivers who paid cash saw their 80 cent toll go up to $1.50.

Other toll plazas now cost even more. For example, the Waukegan Toll Plaza on I-94 now costs $1.40 (I-Pass) and $2.80 (cash).

An interest group, Taxpayers United of America, filed a lawsuit last year seeking to block the increases by challenging the Toll Highway Authority’s right to charge tolls at all. The group said when the tollways were created in 1953, they were supposed to be turned into freeways within 20 years once the original bonds to fund construction were paid off.

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A judge dismissed the lawsuit in December.