Roadway maintenance activities and sometimes water/sewer line repair occur in close proximity to traffic, creating a potentially dangerous environment for workers, drivers, and incident responders. In many cases a Temporary Traffic Control (TTC) zone will be needed to protect both workers and incident responders as well as allow for the safe and efficient movement of drivers and pedestrians through and around the work zone. There are several work zone safety issues to plan and prepare for when setting up Temporary Traffic Controls.
There are seven (7) fundamental principles for TTC zones that should be taken into account on every maintenance project, regardless of size or duration:
1. Plan for traffic safety – road users and worker safety are the highest priority elements.
2. Interfere with traffic as little as possible – avoid abrupt changes to traffic patterns that would require rapid or unexpected maneuvers.
3. Provide clear, positive guidance on how to get through the work zone – give adequate advance warning about upcoming work zones to all users, including drivers, cyclists, and pedestrians (including disabled pedestrians) by using appropriate traffic control devices, such as cones and signs, and by removing or covering any conflicting devices. Provide a safe alternate route for pedestrians when the sidewalk is closed.
4. Perform continuous inspection and maintenance of TTC devices –trained personnel should perform the inspections and schedule the repair or replacement of devices as necessary.
5. Maintain roadside safety throughout the operation – provide a buffer zone for errant vehicles and store equipment and materials where they will not get hit.
6. Make sure workers are properly trained and certified – all those who are involved with planning, installation, maintenance, and removal of work zones should have the appropriate safety and TTC training. (Check with ODOT for state and local requirements.)
7. Maintain good public relations – provide appropriate advance notice and cooperate with news media in publicizing work zones that will impact pedestrian, cyclist, and vehicle traffic.
Work Duration and Appropriate Devices
Work duration and location are key elements in identifying the number and types of TTC devices used in the work zone. Work durations for maintenance work typically fall into three (3) categories:
• Short-term stationary work – occurs during a single work shift and occupies a location for more than an hour within a single daylight period. Cones and portable signs are options for traffic control devices at these locations. Short-term stationary activities include:
o Light standard repair
o Pothole repair or patching
o Bridge or culvert repair
• Short duration work – occupies a location for up to one (1) hour. Portable traffic control devices are an option for this type of work zone, and vehicles may use signs or arrow panels to assist with TTC. Shadow vehicles may also be used for worker safety. Examples of short duration work include:
o Pavement sampling
o Repair and replacement of small roadside signs
o Replacement of raised pavement markers
• Mobile work – moves intermittently or continuously. The same devices and vehicles that apply to short duration work can apply to mobile work. Examples of mobile work include:
o Pavement marking installation
o Pavement sweeping
o Mowing along a roadway right-of-way
o Snow removal
Safety in short duration or mobile operations should not be compromised by using fewer devices simply because the operation will frequently change its location. Warning signs, high-intensity rotating, flashing, oscillating or strobe lights on a vehicle, flags, and/or channelizing devices should be used and moved periodically to keep them near the work area.