Hartsfield-Jackson International has increased its parking fees, a key source of revenue at the world's busiest airport.

Parking in hourly short-term decks in the domestic parking garages now costs $3 per hour for the first two hours, up from $2 previously. The new rates took effect Aug. 1.

The new rates are $4 per hour for the 3rd through 6th hours, and $36 a day after 6 hours. That's up from previous rates of $3 for the 3rd through 6th hours and $32 for 6-24 hours.

"We took a look at our parking rates and recognized we were far below other airports and it was time to institute the increase in parking rates," said Hartsfield-Jackson spokesman Andrew Gobeil.

The maximum daily rates are also increasing to $19 a day for daily parking in the covered decks, $14 a day for economy parking and park-ride reserve, and $10 a day for park-ride lots A and C.

The previous maximum daily rates were $16 per day for daily parking in the covered deck, $12 a day for economy parking, $12 a day for park-ride reserve and $9 a day for park-ride lots A and C.

Hartsfield-Jackson brought in $132.1 million in revenue from parking in fiscal year 2016.

The last time the Atlanta airport increased its parking rates was in 2010. After that hike, the airport's annual parking revenue jumped from $95.6 million to nearly $114.4 million in one year, and the revenues have increased since then.

The airport parking garages sometimes fill up during busy periods, requiring motorists to find somewhere else to park. It can also be difficult to find a parking spot when the garages are full.

Hartsfield-Jackson plans to expand parking as passenger traffic grows, including demolition and reconstruction of the domestic parking garages, as well as new parking facilities to be constructed. The airport's own garages and lots compete with private off-airport lots, which many travelers use as a regular option or when the airport-run lots fill up.

The airport plans to soon start work on a new parking deck to be built near the Georgia International Convention Center, which will be reachable via SkyTrain.

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Hartsfield-Jackson manager on Delta: 'Nobody makes you madder than the ones you care about the most' Parking in hourly short-term decks in the domestic parking garages now costs $3 per hour for the first two hours, up from $2 previously.