In addition to soaring gas prices, NY State drivers now have an additional cost to worry about.

The NY State Thruway Authority’s board of directors have approved a series of toll hikes that managers of the 641-mile superhighway say will raise about $375 million over the next three years.

Drivers who pay cash will see the smallest increase. Cash tolls will go up 5 percent next January and another 5 percent in January 2010.

Those using the EZ-Pass electronic toll collecting system — which provides discounts as an incentive to get drivers to sign up — will see much steeper increases.

Starting this July, a series of reductions in the EZ-Pass discount rates combined with higher toll rates will result in some drivers paying as much as 28 percent more than they do today.