Bicycle accident numbers stay the same, but severity of injuries is increasing.

Helmet use increased during study but did not significantly decrease injuries.

A study titled Increasing Severity Of Bicycle Injuries Leads To Concerns About Cycling Infrastructure raised concerns about the safety of cycling. Abdominal injuries increased 15% and chest injuries increased three-fold. Over the 11 year study period a total of 329 cycling injuries were studied at University of Colorado School of Medicine Rocky Mountain Regional Trauma Center at Denver Health Medical Center, Denver. Helmet use had increased during the study, yet 33 percent of the injuries involved a significant brain injury.

For more articles on the study See: Increasing Severity Of Bicycle Injuries Leads To Concerns About Cycling Infrastructure and Study: Bike Injuries Becoming More Severe.