According to the U.S. Department of Labor, Occupational Safety and Health Administration, one of the requirements of Section 1926.601(b)(4) states (to paraphrase) that no motor vehicle either a truck in construction, earthmoving or compacting equipment, will be permitted to be used should that vehicle have an obstructed view to the rear. Unless that vehicle includes an audible reverse signal alarm, that vehicle is backed up only when an observer signals when safe.
Backup cameras and sensors (if installed), should be capable of informing the driver when they are too close while backing up. Where more modern trucks and vehicles may have these safety systems as standard from the get-go, retrofitting them into older pieces of equipment that may not have the features and capabilities is slightly more challenging. Dakota Micro addresses this exact situation with a portable— and durable—high-resolution video camera.