Frequency of auto injury claims has been falling while theaverage claim cost has risen 18-to-22 percent--driven up by moreexpensive repairs and medical treatment, according to a newreport.

The findings were contained in the Insurance Research Councilstudy "Trends in Auto Injury Claims, 2008 Edition," which documentsauto insurance claim frequencies and costs, both countrywide and bystate, using private passenger auto claim data from national andstate-level statistical reporting agencies.

Researchers examined trends for major auto insurance coverages:property damage liability (PD), bodily injury liability (BI), andpersonal injury protection (PIP).

From 2000 through 2006, property damage claim frequency based onclaims per 100 insured vehicles decreased 11 percent, IRCfound.

Bodily injury claim frequency decreased 19 percent; and personalinjury protection claim frequency fell 14 percent.

IRC said these declines in claim frequencies mirror nationaltrends in fatality and injury rates and indicate significantprogress in efforts to make vehicles, roads and highways safer forthe driving public.

The report also documents an increase in claim severity, or theaverage cost of claims. From 2000 to 2006, property damage claimseverity increased 18 percent; bodily injury claim severityincreased 22 percent; and PIP claim severity rose 19 percent.

On an annualized basis, increases in claim severity from 2000 to2006 averaged 2.9 percent for property damage, 3.3 percent forbodily injury, and 2.9 percent for PIP. IRC said the increases inclaim severity are largely attributable to the rising cost ofautomobile repair and medical care.

In 2006, for all three coverages, claim frequency was found tobe at its lowest point and claim severity was at its highest pointsince 1990.

Decreasing claim frequency and rising claim severity haveresulted in relatively stable loss costs, the average cost ofclaims per insured vehicle. Since 1997, the combined injury losscost for all injury-related coverages has fluctuated just under$200, according to the study.

IRC said loss cost stability "built on a foundation of fallingclaim frequency and rising claim severity raises concerns about thepotential consequences should the favorable trend in claimfrequency end."

"The continued drop in claim frequencies has offset escalatingcar repair and medical care costs," observed Elizabeth A. Sprinkel,IRC senior vice president. "However, if claim frequencies start torise or even just stop declining, then rising claim severities willincrease loss costs, creating upward pressure on premiums forconsumers."