WASHINGTON, D.C Federal officials have wrapped up the investigative phase of a problem-plagued study into the causes of serious bus and motorcoach accidents despite having far fewer crashes to examine than they wanted or initially anticipated.

The Federal Motor Carrier Safety Administration ended the data gathering phase of the Bus Crash Causation Study with only 40 personal injury or fatal accidents to investigate.

Researchers had hoped to have between 50 and 100 crashes to review during the study period.

"The good news is that we did not have as many accidents as we had expected, and the bad news is that we did not have as many accidents as we had expected," said one federal official who asked not be identified because details of the study have yet to be made public.

He said the information gathered during the past two years on accidents in New Jersey now is being put into a format so officials can analyze it and determine what steps the FMCSA could take to reduce the number of serious bus and motorcoach crashes nationwide.

"If we find that drunken pedestrians are walking in front of buses, then there is nothing we can do about it," he said. "But if we find that many of the accidents are caused by bad brakes, then we could look at mandating more brake inspections."

He said the review probably will begin sometime after the end of May and could involve both FMCSA officials and a private consultant. The final study results are not expected until December.

Despite not having as many accidents as desired, the official said the number of crashes for which data has been collected is likely to produce enough information to make the study valid.

The study, initially set to last one year, began in January 2005 in a target area that covered the northeastern section of New Jersey, a state in which numerous serious bus and motorcoach accidents have occurred over the years. However, by the end of 2005, only 23 serious accidents were recorded and the FMSCA decided to extend the study a second year and widen the target area to cover the entire state.

The FMSCA said it selected New Jersey because it has a good mix of types of bus and motorcoach operations professional motorcoach charters and tours, private church transportation, commuter runs and inner city transit.

The United Motorcoach Association and others were critical of both the initial study plan and the extended and expanded plan, contending it did not cover a large enough area to produce enough meaningful information to reach valuable conclusions.

The critics also warned that the results of the study could be skewed because of New Jerseys robust bus safety enforcement program.

"It has been UMAs experience that states that employ strict bus enforcement programs are the least likely jurisdictions to have high crash occurrences," the UMA wrote in a filing with the federal agency before the study began.

The trade group and other critics recommended that the study area cover all 50 states and researchers pay close attention to the differences in accidents in states with aggressive programs versus those with weak or nonexistent programs.

UMA was joined in its criticism of the study limits and methods by the Insurance Institute for Highway Safety and Advocates for Highway and Auto Safety.

The FMSCA plans to pool the data gathered in the study with information from existing accident and insurance databases to find out the types of accidents that are occurring most often and what might be causing them.

An already-completed truck crash study and the bus and motorcoach study were mandated by the Motor Carrier Safety Improvement Act of 1999.