WASHINGTON—A recent study by a trial lawyers group showing that more than 28,000 motor carrier companies have violated federal safety regulations drew the ire last week of the American Trucking Assn.

The American Assn. for Justice, formerly called the American Trial Lawyers Assn., said car drivers are sharing the road with trucks that have “incurred thousands of safety violations” and, as a result, preventable truck accidents are occurring.

Trucking companies are “violating safety standards to cut corners and maximize profits,” the AAJ said.

In addition, the minimum insurance requirement for commercial trucks, which has stood at $750,000 per truck since 1980, is “completely inadequate,” the Washington-based AAJ said in a statement.

But the ATA fought back, saying the commercial trucking industry is getting safer every year and that many of the safety violations cited by the AAJ are paperwork issues that have “no effect on safety.”

In addition, a spokesman for the ATA said 28,000 motor carriers cited in the report constitute less than 5% of the total number of motor carriers in the United States, which is 579,759, according to the U.S. Federal Motor Carrier Safety Administration.

And studies by Virginia Tech and the American Automobile Assn. show that 78% to 80% of all car-truck crashes are caused by the driver of the car, the spokesman for the Washington-based ATA said in an e-mail. The ATA also noted that car-truck collisions became such a problem that the U.S. Department of Transportation partnered with state police nationwide and had representatives ride with truck drivers to observe unsafe actions by car drivers.

“The large-truck crash rate, injury rate and death rate are all at historic lows,” the ATA spokesman said in the e-mail. “Trucking is the safest it has been since the DOT began keeping these statistics in 1975.”

Dan Golden, senior director of commercial insurance for the Property Casualty Insurers Assn. of America, agreed with the ATA that trucking has become safer throughout the years. He also said that raising the minimum insurance requirements for trucking companies might price many companies and owner-operators out of the trucking business.

The AAJ argued in its study that the $750,000 minimum level of insurance, when adjusted for inflation since 1980, is roughly equivalent to $292,000. The AAJ acknowledged that larger motor carrier companies buy much higher limits than the required minimum, but that smaller companies often carry only the minimum insurance.

In its analysis, the AAJ said 87% of the trucking companies in violation of safety standards are small companies that have fleets of 10 trucks or less.

“The current minimum insurance requirements are woefully inadequate and punish injured consumers twice by leaving them to bear the burden of uncovered health care costs,” AAJ President Anthony Tarricone said in a statement.

But Mr. Golden said if the minimum insurance requirement was such an issue, people or groups other than the AAJ would be clamoring for a change. He noted that trucks carrying light hazardous materials must have at least $1 million in insurance and those carrying hazardous materials must have at least $5 million in insurance per vehicle.

“If (the raising of this issue) was happening on a regular basis—that truckers do not have adequate insurance limits—it might be more of an issue. That's just not happening right now,” Mr. Golden said.