Nearly 7 million vehicles on U.S. roads have an unrepaired recall tied to their backup camera systems, according to new Carfax data.

Since the start of the year, the number of backup camera recalls has risen by more than 1.5 million, which is no surprise since back-over prevention systems were the leading cause of recalls last year by volume, according to risk-and-claims administration and data provider Sedgwick.

Carfax said that the recalls stem from a variety of issues, including blank or distorted screens, frozen images and intermittent camera failures. It pointed out that the issues “can reduce driver visibility and increase the risk of a crash.”

“Backup cameras are a critical safety feature and when they don’t work properly, can significantly limit what drivers see behind them,” said Carfax Vice President of Data Acquisition Faisal Hasan.

The rise in camera-related recalls could be attributed to several factors, Carfax said. Since most new vehicles sold in the U.S. are federally required to have backup cameras, minor malfunctions can become safety compliance issues. And as automotive technology advances and systems become more interconnected, there is greater chance of widespread failures.

With the sheer number of active recalls, dealerships would benefit from building recall management into their service drive processes.