Mobile & Short-Duration Work Zones
Not every road job is a fixed work zone. Crews paint stripes, patch potholes, sweep, mow and inspect while moving slowly, or stop for minutes at a time. With no cones and barriers, the crew depends on warning vehicles, lights and signs to alert drivers going at full speed. These zones have a high rate of rear-end crashes into work vehicles.
- Road Maintenance Crews
- Utility Crews
- Striping & Sweeping Crews
- Flaggers
Types of temporary traffic control
The Manual on Uniform Traffic Control Devices (MUTCD) groups work by how long it stays in one place:
| Type | Description |
|---|---|
| Long-term stationary | Work in one place for more than 3 days |
| Intermediate-term stationary | More than one daylight period up to 3 days, or nighttime work longer than 1 hour |
| Short-term stationary | Daytime work lasting more than 1 hour within a single daylight period |
| Short duration | Work lasting up to 1 hour |
| Mobile | Work that moves intermittently or continuously, like striping, sweeping and herbicide spraying |
Each type has different signs, devices and vehicle needs. The shorter the stop, the more crews are tempted to skip protection, which makes short-duration work one of the most dangerous. See Work Zones.
Main hazards
- Rear-end crashes into slow work vehicles by drivers who don't see them in time.
- Large speed differences between the crew and traffic.
- Workers on foot getting out of vehicles into the lane.
- Backing and turning maneuvers. See Backing & Spotters.
- Night and low visibility. See High-Visibility Clothing.
- Distracted and impaired drivers.
Protection for mobile and short work
- Use a protection vehicle (shadow truck) with a truck-mounted attenuator where required, and an arrow board or message sign to guide traffic. See Truck-Mounted Attenuators & Shadow Vehicles.
- Add advance warning: signs such as "Road Work Ahead" and "Right Lane Closed Ahead" on a vehicle or trailer upstream of the work, at the distance the plan calls for.
- Use high-intensity rotating, flashing or strobe lights on work vehicles as the MUTCD and your agency require. Keep the lights on while workers are on the road.
- Keep the spacing between the work vehicle and the shadow truck as the plan says, which allows stopping distance and reduces the chance of a pushing impact.
- Stay in constant radio contact between the crew, the shadow vehicle and the lead vehicle.
- For short stops, still park the work vehicle so it protects the crew, turn on lights, and use cones if the stop will be more than a few minutes or the plan requires. Never let "just a minute" turn into long unprotected work.
- Wear Class 2 or Class 3 high-visibility apparel, a hard hat and reflective gear. Use a flagger when required. See Traffic Control Crews.
- Plan entry and exit from vehicles on the side away from traffic, and don't work with your back to traffic without protection.
- Hold a briefing on the route, roles, hazards and emergency plan before each shift.
Mobile zone checklist
- I know whether this job is mobile, short duration or stationary under the plan
- A protection vehicle with arrow board and lights is in place
- Advance warning signs are set at the planned distance
- The crew has radio contact and wears high-visibility clothing
- I don't let short stops become unprotected work
Standards & references
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