CHULA VISTA, Calif. -- Around 30,000 drivers use the South Bay Expressway each workday, but the new privately run toll road has failed to fuel the business boom Chula Vista merchants were hoping for, it was reported Monday.

The four-lane tollway debuted nearly six months ago. It's 10 miles long and connects the East County to the South Bay.

Chula Vista Mayor Cheryl Cox told The San Diego Union-Tribune that some merchants in the area are disappointed in the tollway's generation of new customers so far. She said she wonders if expectations surrounding the $843 million project 17 years in the making were too high.

"Sometimes anticipation is greater than realization," Cox told the newspaper.

Chula Vista's sales tax revenue did increase late last year with the holiday shopping season, but business quickly slowed in January, according to the Union-Tribune.

The cost to use the toll road increased after the holidays.

"I've had customers say they couldn't believe how expensive the road was," Jean Riley, who manages Geppetto's toy shop in Otay Ranch Town Center, told the Union-Tribune.

Tolls range from 75 cents to $3.75, depending on the length of the trip and whether it's paid with cash or through the same electronic toll system -- FasTrak -- used in other parts of the county.

South Bay Expressway Ltd. Partnership built and will manage the road for at least 35 years until it is supposed to be turned over to the state, the Union-Tribune reported.