NEW YORK (CNN/Money) - Cell phones and other wireless devices contributed to the most automobile crashes, near-crashes and other incidents, according to a published report of a government study due to be released later this month.

The Wall Street Journal reports that the study done by Virginia Tech for the National Highway Traffic Safety Administration videotaped 100 cars and their drivers for a year, covering about 2 million miles and 43,000 hours of driving.

The use of wireless devices were involved in what the report said were 644 "events," which includes crashes, near-crashes and having to take evasive maneuvers. There were six actual crashes while drivers in the study were on the wireless devices, according to the newspaper's report.

The majority of those occurrences, including all crashes, happened while drivers were on the phone talking and listening, rather than dialing a phone number.

The next-biggest distraction, with 411 events, came from "passenger-related" issues, including talking to a fellow passenger and placating children in rear seats.

A spokesman for the Cellular Telecommunications and Internet Association questioned the report, saying its findings were out of line with earlier studies.

"Acknowledging that cell phone use in a car can be a potential distraction ... we've been very clear on that," a spokesman for the industry's trade group said. "At the same time, cell phone use is one of what appears to be a number of behaviors in there."

The newspaper said another NHTSA study that looks at driving and phone usage, presented at a traffic-safety conference last week, raises questions about the added safety benefits of using headsets and other "hands-free" devices.

Drivers kept both hands on the wheel only about 13 percent of the time when not on the phone, according to the Journal. While those with "hands-free" phones kept both hands on the wheel about the same percentage of time, it fell to only 1 percent for those on the phone without such equipment, according to the report.

But the newspaper said that the NHTSA, while it can make regulations about some auto safety equipment, does not have power to set rules about cell phone use in vehicles.

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