Eight of Illinois' 30 interstate rest areas that have been closed are set to reopen this fall.

According to reports, maintenance was required at the closed facilities, but it's not clear why most of it happened around the same time period, Paris Ervin, a spokeswoman for the state Department of Transportation.

The Salt Kettle rest area, on Interstate 74 west of Danville, parts of the Silver Lake rest area, along Interstate 70, and the Gateway rest area, Interstate 64 near St. Louis, have been undergoing bathroom renovations and upgrades.

The Funks Grove rest area, south of Bloomington on Interstate 55, has been shuttered the longest. It was closed in spring 2013 because of a septic system failure.

The Trail of Tears rest area along Interstate 57 near the Missouri border has been closed for sewer work since July.

The Pride of the Prairie rest area on Interstate 72 was closed last month for a pavement project, while the Coalfield rest area on Interstate 55 was closed for roofing repairs.

The closed rest areas should all be reopened by November. The cost of the work was not immediately known.