July 8, 2019 | Matt Stubblefield, Horizon Signal Technologies

During a recent construction project on Rucks Dairy Road in Lake Okeechobee, FDOT faced a dilemma.  Seven individual driveways fell within the one-lane work zone that would be active for the next four to six months.  The residents using these driveways every day would need an indication telling them when it was safe to exit their driveway, and enter the work zone. Placing a flagger at each individual driveway would not be feasible -- not just because of cost, but also because of the increased cycle lengths and queues caused by holding the mainline traffic while driveways were given the right-of-way one at a time.  FDOT wanted to keep traffic moving as efficiently as possible, and elected to use a new temporary traffic signal system called the Driveway Assistance Device, or “DAD,” from Horizon Signal Technologies.  This system allows each driveway within a work zone to be serviced simultaneously during every cycle.  Flashing arrows are displayed in the direction of traffic flow, allowing drivers to join or follow the flow of alternating traffic out of the work zone in the displayed direction. Once vehicles clear the zone, traffic flows in the opposing direction, and all arrows flash accordingly.  No dedicated time is needed for individual driveways, and cycle times are kept to a minimum.  Trailer-mounted red/yellow/green signals were installed at both ends of the lane closure to control alternating mainline traffic. Additionally, a DAD unit was installed at each of the seven driveways on Rucks Dairy Road and operated for the entire duration of the project. The local residents reported that the system made them feel safer when leaving their driveways, and reduced their uncertainty when entering the work zone.  Due to the success of the project, FDOT is working to add the Driveway Assistance Device to the Approved Products List for use on future projects.