A preliminary review by the Transportation Research Board indicates possible weaknesses in the Department of Transportation’s Comprehensive Truck Size and Weight Study. Opponents of higher limits seized on the review as evidence for their cause.

As part of a peer review process, a TRB committee examined “desk scans” or surveys of past research that the department is using to inform its study.

The committee found that the scans contain the documentation needed to support the analysis methods DOT will make. “However, in most cases the selection of methods appears not to have been a consequence of the desk scans,” the TRB committee says in its report.

TRB surmises that the shortcoming may have arisen because Congress did not give the department enough time to do the study.

Congress ordered the study in the 2012 highway law to help answer the difficult policy and political question of whether or not to raise the national size and weight limits. The analysis is due next October in preparation for the next highway bill.

TRB recommended that the department continue work on the scans by including additional analysis covering alternative methods of calculating the impact of changes in the limits.

This finding by TRB gave ammunition to opponents of higher size and weight limits.

“I have serious concerns about the study that the Department of Transportation is conducting on this critical issue,” said Rep. Jim McGovern, D-Mass.

“We want and need the best possible study, and if the process is flawed, this will all be an exercise in futility.”

McGovern was joined at a Wednesday press event by Jimmy Hoffa, general president of the Teamsters union, Joan Claybrook, chair of Citizens for Reliable and Safe Highways, and Jackie Gillan, president of Advocates for Highway and Auto Safety.

The advocacy groups also released a report by the Multimodal Transportation and Infrastructure Consortium, done at Marshal University in West Virginia, that found longer and heavier trucks have a higher fatal crash rate than current standard configurations.

The DOT study, which is being conducted by the Federal Highway Administration, is well down the road. Late last year the agency announced it has chosen the types of trucks it will analyze. The next public update is due May 6.