OSHA requirements are set by statute, standards and regulations. Our interpretation letters explain these requirements and how they apply to particular circumstances, but they cannot create additional employer obligations. This letter constitutes OSHA's interpretation of the requirements discussed. Note that our enforcement guidance may be affected by changes to OSHA rules. Also, from time to time we update our guidance in response to new information. To keep apprised of such developments, you can consult OSHA's website at https://www.osha.gov.

July 23, 1979

Mr. George W. Tinkham
Assistant Chief Counsel
Illinois Department of Transportation
2300 South Dirksen Parkway
Springfield, Illinois 62764

Dear Mr. Tinkham:

This is in response to your recent inquiry requesting additional information for specific Construction Safety and Health Regulations.

The intended meaning of the words "audible above" found in 29 CFR 1926.601(b)(4)(i) is to require a signal alarm distinguishable from the surrounding noise level. As indicated in your letter, 29 CFR 1926.602(a)(1) does apply to "off-highway trucks." Trucks, including dumpers, designed for off-highway operations at a construction site must comply with the 29 CFR 1926.602 requirements.

We hope this information will be helpful to you. If we may be of any further assistance, please feel free to write or call.

Sincerely,



Grover C. Wrenn Director,
Federal Compliance
and State Programs