The number of people killed in traffic crashes in Iowa climbed over 100 earlier this month and now the busy summer driving season is here.

Dennis Kleen tracks crash data for the Iowa Department of Transportation. “Once summer gets here, you’ve got people on vacation and a lot more people driving during the summer,” Kleen says. “Put the phone down and buckle up. Those are a couple of the best things you can do.”

There were 320 people killed in traffic crashes in Iowa in 2015. Last year, that number rose to just over 400.

Kleen suspects distracted drivers, people who are texting or doing something else with their phone, are causing more crashes. “It’s hard to prove that someone was distracted in a fatal crash…unless there were actual witnesses and a lot of times, there aren’t (witnesses) in many of these crashes,” Kleen said. “But, we’ve all seen people using their phones as we’re driving, so we know distracted drivers are a big part of these crashes.”

The Iowa legislature this year passed and Governor Branstad signed a bill in to law that will allow police to pull over drivers who are looking at their cell phone rather than the road. The fine for a texting-while-driving ticket will be $30 when the new law takes effect on July 1.