The styling of bike helmets has come a long way, but the sporty look masks a serious job – making sure riders are protected from a serious head injuries.

Consumer Reports just tested models for kids and adults and made some recommendations.

When cars and bikes collide, too often the bicylist is seriously hurt if not killed. As Brent Mather knows, a good, well-fitting helmet can make all the difference.

"I was hit by a car several years ago," Mather said. "And if it wasn't for the helmet, I'm pretty positive my injuries would have been far worse."

Consumer Reports just tested helmets to see which ones really provide the protection you can count on. They assessed both adult and youth sizes on all kinds of testing contraptions they came up with to see how well they do the job.

The first test checked to make sure the helmet will stay in place. The machine assesses whether the chinstraps will stretch, break or open upon impact. All 13 bike helmets passed.

The next test checked how well a helmet will protect the head upon impact in a variety of scenarios.

"The impact test simulates what happens when a helmet impacts different surfaces, like a flat surface like a street, a rounded triangle like a curb, and a hemispherical surface, which simulates hitting a rock," said Rich Handel of Consumer Reports.

Two adult helmets did poorly: the Nutcase Street Sport 8 Ball and the Bern Brighton Thin Shell EPS for women.

On the plus side, two helmets rated very good for impact resistance: The $60 Specialized Echelon for adults and for children, the $45 Bontrager Solstice Youth.

But in order to protect the head, a helmet must be worn properly. It should be level on the head, with no more than one or two fingers-width above the brow. The straps should form a "V" under each ear with the buckle centered under the chin. It should fit snugly. Riders should be able to shake the head back and forth without the helmet moving even before the strap is tightened.