Abstract: Employee #1 and Employee #2 were cutting out and replacing lintels in the window openings of existing condominiums while working from a JLG Model Number 600A articulating boom aerial lift that was parked on a 2-way residential street with a posted speed limit of 15 miles per hour. The aerial lift and the elbow of its boom obstructed up to 11.5 feet of the street which varied from 23 to 26 feet wide. Suddenly, an 11,500 pound U-Haul truck came down the street and struck the elbow of the boom, knocking Employee #2 out of the basket, and jolting Employee #1. Both employees were wearing personal fall arrest harnesses. Employee # 2, fell six feet while wearing a personal fall arrest system. The work zone was not posted with advance traffic warning signs, and traffic channelization devices; employees were not trained in work zone setup requirements and the employer did not have a competent person inspect the work zone to ensure compliance with the requirements of for temporary traffic control as delineated in Part VI of the Manual on Uniform Traffic Control Devices.