PORTLAND – The Maine Turnpike Authority voted to keep the current E-ZPass volume-based discount program in place indefinitely, maintaining a popular program that gives discounts to daily commuters.

The current discount rates were initially approved by the board as a phase-in plan set to expire on July 1.

“We listened to commuters very closely and recognized their concerns. it is clear that the new discount plan is popular and working well, so we are going to mainain it long-term,” said Executive Director Peter Mills.

Maine E-ZPass account holders who take at least 40 one-way trips a month get an additional 50 percent off their entire bill for that month. Those who make between 30 and 39 one-way trips get a 25 percent discount. Maine E-ZPass rates are already set lower than cash tolls for most turnpike trips, even before the volume discount is applied, the turnpike authority said.

The new discount plan is expected to save Maine Turnpike E-ZPass customers about $6 million a year in tolls – more than three times the amount under the old commuter plan. More than 27,000 Maine E-ZPass commuters had their toll rates lowered 50 percent in April. Another 9,600 received a 25 percent discount. Nearly 20,000 new Maine E-ZPass devices have been sold since the new plan was implemented in November, 2012.

“We’re raising just enough revenue to meet the needs of the turnpike while still allowing us to deliver a very substantial discount to commuters using a Maine E-ZPass,” Mills said.

Last year, the Maine Turnpike Authority had increased tolls at various spots along the 106-mile highway. From November 2012 through April 2013, turnpike authority said revenue increased by 16 percent even as the number of cars on the turnpike dropped by 4 percent. The number of E-ZPass holders totaled about 209,000, or 1 in 6 Mainers.