Sandy Springs adopted an ordinance Tuesday requiring developers to pay impact fees to offset the expense of growth-related improvements in transportation, public safety and parks.

The city plans to direct as much as 80 percent of the money to transportation improvements. Fees vary depending on the size and type of development, and whether it is replacing existing structures.

For example, condo developers building on undisturbed land will pay the city $1,136 per unit – $165 per unit for parks and recreation, another $165 for public safety and $806 per unit for transportation improvements.

Fees for transportation improvements are the heftiest and are based on car trips generated by the new development. Under the schedule, developers of 24-hour convenience stores pay the highest fees, or $39,591 for each 1,000 square feet of space.

By comparison, a nursing home developer would pay $326 per bed.

Approved by the City Council in a unanimous vote, the impact fee requirement takes effect March 1.

Fees would be paid by developers as a requirement to obtain a building permit. They are not retroactive. Developers who have already received a building permit and have begun construction on projects will not be affected.

Several Atlanta-area cities and counties already have impact fees, including Fulton, Atlanta and Roswell. The state authorized impact fees in 1990 to offset the cost of new growth.

Bill Gannon, a city resident who was among seven residents on an advisory committee, said the fees are fair to developers and the city's residential taxpayers.

"We had a strong consensus," Gannon said. "If you didn't charge the developer something, you're putting too much of a burden on the neighborhoods."