Here is the latest Iowa news from The Associated Press

DES MOINES, Iowa (AP) – An effort to improve teen drivers’ road safety by limiting their number of passengers is having little impact, because most parents are signing waivers to opt their 16- or 17-year-olds out of the requirement. For the first six months of an intermediate license, drivers can’t have more than one unrelated minor passenger when driving without adult supervision. But the 2013 law allows parents to make the decision on whether to exempt the child. The Iowa Department of Transportation says about 90 percent of parents signed waivers in 2014.

MOLINE, Ill. (AP) – Officials say a towboat operator inadvertently pumped about 50 gallons of an oil and water mix into the Mississippi River, but the spill has been cleaned up. Moline Fire Department Captain Brian Vyncke tells the Quad-City Times the U.S. Coast Guard determined that oil somehow got mixed in water that was being pumped out of a towboat owned by the Celebration Belle excursion boat Friday afternoon.

DES MOINES, Iowa (AP) – Summers will be a steamier in neighborhoods across the country as crews cut down millions of trees in an effort to stay ahead of a small, shiny bug. In cities like Waterloo, Iowa, workers are in the midst of taking out 4,000 ash trees that tower over homes and shade city streets.

ALGONA, Iowa (AP) – An Iowa couple is donating $5 million to build Algona High School’s new performing arts center and auditorium. The Mason City Globe Gazette reports Ed and Betty Wilcox agreed to donate the money over the next five years.