The explosive expansion of dockless e-scooters from startups like Lime and Bird in cities all around the world has made it super easy to get around. But you know what's not so great about the two-wheelers? When you inevitably face plant into the ground.

E-scooter injuries are on the rise and now the Centers for Disease Control and Prevention (CDC) wants to better understand how riders are hurting themselves as well as the severity of their injuries while scooting around town. And surprise: the reasons are super obvious.

Contrary to popular belief, most e-scooter-related injuries don't happen at night and don't involve collision with a car, according to Jeff Taylor, manager of the Epidemiology and Disease Surveillance Unit with Austin Public Health.

"Our study will show they occur during all times of the day," Taylor said. "People may also perceive there’s typically a car involved. But our study finds most of the time the rider may hit a bump in the road or they simply lose their balance."

The CDC's study, which will be released in the spring, showed fewer than 1 percent of e-scooter riders wore helmets.

Similarly, the University of San Diego Medical Center's tracking of e-scooter-related injuries showed 98 percent of patients who got into accidents didn't wear a helmet, 48 percent of them were drunk, and 52 percent tested for substance abuse.

UCLA researchers who looked at data for patients admitted to its medical centers between Sept. 2017 and Aug. 2018 also found most e-scooter injuries were from falls.

One person profiled by CNBC said she landed in the emergency room with a busted lip when she hit a pothole.

So who's to blame for the increase in e-scooters? The e-scooter startups that are taking over cities? Irresponsible riders? The cities for not creating proper pathways (like bike lanes) to accommodate e-scooters?

That's what the CDC's hoping to figure out. But from what little data that already exists, it's clear everyone shares a little bit of the blame. Riders for not wearing helmets and riding on scooters when they're under the influence. Scooter companies for not creating protections that check for things like intoxication and helmets (a difficult undertaking, but with great power comes great responsibility). And of course, cities also share the blame for not adapting quickly enough to changing transportation trends.

"We’re taking this issue seriously. We’re doing all that we can to work with cities, education and technology to address these accidents and it’s encouraging the medical community is as well," a Lime spokesperson told CNBC. "We absolutely support the CDC study and would love to contribute in any way through data sharing."

E-scooter startup Bird also told CNBC it's spoken to the CDC researchers and doesn't disagree with its early assessment. "People will always make mistakes on the road, but it’s not about perfecting human behavior. It’s about designing streets so when people make mistakes those mistakes aren’t fatal," a Bird's safety policy director Paul White said.

As we said, these findings are sorta obvious. So be smart and safe and wear a helmet, and never ride a scooter if you're wasted. Just don't do it. You risk hurting yourself and others. It's no different than the rules that apply to driving a car.