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Horns and reverse alarms on bulldozers

Summary A construction trade association asked how the horn requirement differs from an audible reverse alarm and whether a bulldozer can use an alarm or signaler instead. OSHA said the horn provides a warning as needed, while a reverse alarm sounds throughout backward movement. It said the horn requirement still applied when a bulldozer had a bidirectional alarm or a signaler directed forward movement.
Document
Federal opinion letter
Agency
Occupational Safety and Health Administration (OSHA)
Document number
1987-09-23
Date issued
September 23, 1987
Status
Active
Status last verified October 10, 2026
Topics
Workplace Safety OSHA 1926 Construction Equipment Audible Warnings
Source
View the official document

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About this page: The full text below is the official document from Occupational Safety and Health Administration (OSHA). Ezel adds the plain-English summary and tracks the document's status. The official source linked on this page is authoritative for any reliance.

Robert Peyton, Director
Safety and Health Services
The Associate General Contractors of America
[Recipient address omitted]

Dear Mr. Peyton:

This is in response to your letter of August 24, regarding the problems associated with the definition, application and use of the term "Horns" as used in 29 CFR 1926.602(a)(9)(i).

Our response to your questions is as follows:

  1. What is the definition of a "Horn" as used in 29 CFR 1926.602(a)(9)(i)?

A device sounded to provide a warning to employees exposed to the movement of the machine and the work being performed by the operator of the equipment.

  1. What is the difference between the term "Horn" and audible alarm?

The audible alarm will give an audible signal suitable for the job conditions. The audible signal will provide the alarm during the entire time of backward movement, the horn is only to be sounded as necessary.

  1. If a Bulldozer is equipped with a Bi Directional alarm is a horn required?

If a Bulldozer is equipped with a Bi Directional alarm 29 CFR 1926.602(a)(9)(i) which requires the horn is still enforced.

  1. If a signal man is used to direct equipment in forward motion is a "Horn" required?

If a signal man is used to direct equipment in forward motion 29 CFR 1926.602(a)(9)(i) which requires the horn is still enforced.

If we can be of further assistance, please let us know.

Sincerely,
Thomas J. Shepich, Director
Directorate of Compliance Programs

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