State lawmakers are considering legislation that would enable the state to operate a network of express toll lanes around metro Atlanta — and keep the tolls on the roads permanently.

Previously, when the state wanted to build a toll road, it used the tolls to pay for construction of the new lanes and, once that bill was paid, ended the tolls. For example, the tolls generated on Ga. 400 were imposed to repay the cost of building that highway. Later, the state took on new debt for 14 other projects and extended the tolls on 400 for three years. This infuriated many drivers, who believed that the tolls would end when the construction costs of Ga. 400 were paid off. The tolls have since been lifted.

However, the purpose of the new express toll lanes being built along I-75/I-575 North in Cobb and Cherokee counties and on I-75 South in Henry and Clayton counties is different. They are meant to give drivers the ability to avoid congestion by using a free-flowing lane — for a price. The state plans to complete an entire network of express toll lanes around metro Atlanta, if and when funding becomes available.

The purpose of the bill passed by the Senate Transportation Committee on Monday is to update state law to reflect the new type of toll lanes soon to be in operation, state officials said.

Chris Tomlinson, executive director of the State Road and Tollway Authority, said state transportation planners have been careful to communicate to the public throughout the planning process that the tolls on the new express lanes under construction will be here to stay.

Sierra Club lobbyist Neill Herring worried the bill (SB 125) as currently worded could go even farther than that. He testified before the committee that some ambiguous language in the bill could enable the state to usurp existing interstate lanes and charge drivers a fee for using them. That idea proved wildly unpopular with the introduction of the I-85 HOT lane in 2011. After an initial public backlash, Gov. Nathan Deal said he would no longer allow existing interstate lanes to be tolled.

SRTA officials said that is not the case. Currently the federal government does not allow states to begin tolling free lanes. If it did — as some in Washington have proposed — it would take the actions of both Georgia Department of Transportation and SRTA to establish one, said Tomlinson.

The language in the bill that some contend is too ambiguous already existed under Georgia law, so it wouldn’t grant SRTA any power it didn’t already have, said Deputy Executive Director Bert Brantley.