WICHITA, Kan. -

More than a week after a law enforcement officer and his wife were killed in a crash, Great Bend Police are testing parts of the trailer that caused it.

Reno County jail deputy Shawn Schellenger and his wife, Danielle, died when the trailer came unhitched from a truck, crossed the center line, and hit them on a motorcycle. Great Bend Police sent the ball and hitch used to pull the trailer off for testing. They're looking to see if wear and tear caused it to come unhitched. Prosecutors are waiting for that information to decide if charges will be filed against the driver of the truck.

Safety measures are required on trailers in Kansas but state inspections are not. Kansas Highway Patrol Trooper Gary Warner says it's the driver's responsibility to make sure trailers are properly attached.

"I've stopped a lot of people towing trailers through my career," said Warner. "They haven't taken time to attach the safety chains. They haven't taken time to plug the lights in."

FactFinder 12 asked Warner for the steps to do your own inspection. He says it is vital to know what size ball to use on your trailer so it connects tightly.

"A two-inch would slip on to an inch and seven-eighths ball, but it wouldn't be tight and it may come off," said Warner. The hitch is required by state law. Warner says a hitch pin is necessary for safety.

Kansas law requires safety chains to be attached as a backup catch if the hitch breaks. Warner says it is best to cross one over the other.

"If the hitch would fail, that would allow the chain to cradle the tongue so the tongue doesn't dive into the pavement," said Warner.

After you raise the jack, the lights need to be plugged in.

"If the lights aren't plugged in, the people behind you can't tell whether or not you're stopping or turning," said Warner. "I've worked crashes where that's led to the crash where somebody's rear-ended a trailer."

Warner says to check your four-way flashers, your left and right turn signals, and your brake lights. If any of the lights are not working, Warner says you're breaking the law.

"Even though it takes a few minutes to do this, it's critical it's done every single time before they tow a trailer," he said.

If the safety measures fail, Warner says you need to have your rear-view mirror set to see the entire side of your trailer as you drive. Even though the state does not inspect each trailer individually, Warner says a proper inspection by the driver can save lives.

Trailers weighing more than 2,000 lbs., including the load, must be registered. Anything weighing less does not need a state tag.