The Department of Transportation will not deliver its comprehensive study of the truck size and weight issue on time. In an email notice Monday, the department said it will delay delivery of the study until next year.

“We recognize many people, including Congress, are eagerly awaiting the release of the report,” DOT said.

“However, the department is committed to producing the most objective, data-driven report possible. Based on the current status and the scope and importance of the task at hand, we have had to delay completion of the study until 2015.”

The study was due this fall as part of preparation for the next highway bill. The bill also was originally due this fall, but Congress pushed it back to next May because it could not resolve political differences over how to pay for the federal highway program.

The study is intended to give Congress an objective assessment of the controversial issues surrounding truck sizes and weights.

Large trucking companies and shippers say the current federal limits are outdated and are preventing productivity increases that could go a long way toward relieving highway congestion and improving safety.

Just as assertive on the other side are owner-operators, safety advocates and labor unions that say heavier trucks are an unacceptable safety risk. And the railroads oppose any capacity increase for trucks.

The 2012 highway bill ordered DOT to do a comprehensive analysis to provide Congress the background for a decision.

The work is being done by the Federal Highway Administration, which is looking at the safety and economic implications of changing the federal limits.

The study will compare trucks operating at current size and weight limits to bigger and heavier trucks on the basis of crash rates and other safety risk factors, as well as the costs of effective enforcement, and the impact of the equipment on pavements and bridges. It also will look into the impact on truck-rail competition.

In its notice Monday FHWA said that it is accepting comments on the work done so far. More information is available on the agency’s website.