"I noticed my bike helmet cracked, and at that moment, that's when I realized this helmet saved my life," said Hoffman.
Now, Lisa is known as the "helmet crusader."
Whether you ride on the main streets, or like to hit the back roads, helmets are an essential accessory.
"Wearing a bicycle helmet is the single most important thing that you can do to determine whether or not you live or die from a bicycle accident," said Dr. Melissa Barton of the American College of Emergency Physicians.
Barton said even a light blow to the head can be serious. Possible injuries range from bruising, broken bones and lacerations to concussions and more.
"We see all types of brain injuries and internal bleeding in the brain," said Barton.
The doctor said that as we age, we need to be particularly careful, because our brains begin to shrink as young as when we're 30.
"The space between the skull and the brain gets larger, and that empty space has very tiny blood vessels. So riding a bike without a helmet and hitting your head, can cause those little tiny blood vessels to tear," said Barton.
Style is just one of the reasons adults tend to skip the headgear.
"[Adults] didn't wear one as a child, and so they really don't see the need for it," said Randy Swart of the Bike Helmet Safety Institute.
Barton said her patients also blame cost. However, many helmets nowadays are as little as $10. Swart's organization recently pitted lower priced brands against their expensive counterparts.
"What we found was there weren't any differences. Therefore, everybody ends up with about the same impact protection. You can buy the cheapest thing on the market and still get the helmet you need," said Swart.
But fit is also important. Not only should your helmet be level, but it should touch all the way around.
Swart said a helmet should last at least five years, and if you crash, it should be replaced immediately. Riders also need to be mindful of the sun, because it can make a helmet shell brittle, meaning it will need to be replaced sooner.