LANSING (AP) — The Michigan Department of Transportation gave the gravel industry considerable influence in a state-funded study that found looming shortages in materials used to build highways, potentially undermining the report’s credibility and wasting taxpayers’ money, auditors said Friday.

An investigative audit issued by the state Office of Auditor General also concluded that the agency inappropriately split the study into two separate contracts and did not ensure that the terms were met. Auditors flagged “numerous deficiencies” with the rushed study that cost approximately $100,000, including poor project scoping.

The audit came to similar conclusions as one issued three weeks ago by the Transportation Department. It was done after a complaint was filed in June following a Detroit Free Press report that the Michigan Aggregates Association — a lobbying group for the gravel, sand and crushed stone industries — was behind the commissioning of the study in 2016 and 2017.

Needham has cited the report in legislative testimony about road building and to push legislation, which died last year, to restrict local governments’ ability to deny mining permits. The industry has been frustrated by local “not-in-my-backyard” fights against mining operations that could lower construction costs.

The latest audit included a review of emails and other documents indicating that former Transportation director Kirk Steudle ordered staff to involve an “industry stakeholder” in a market study.