Worked Example: Tree Removal Beside an 80 km/h Road

Tree removal traffic control beside an 80 km/h road is built around the drop zone: a lane or shoulder closure with reduced speed handles the routine work, and short, fully controlled traffic holds cover every cut that could reach the road. The crew runs each hold with a fixed radio script and clears debris before releasing traffic.

This article walks through an example job from planning to pack-down. It is a teaching scenario, not a real project. The approved traffic guidance scheme (TGS), permit and the arborist's own safe work method set the details, and the TGS must be prepared by a suitably qualified person. This is general information, not legal, engineering or arboricultural advice. For the general approach to arborist work near roads, see traffic control for tree lopping and arborist work.

The example site

Example scenario: a council has engaged an arborist contractor to remove a large dead eucalypt on the verge of a two-lane, two-way road signed at 80 km/h on the edge of town. The tree leans towards the road. There is a gravel shoulder, a table drain, and a gentle bend about 250 metres to the north that limits sight distance for southbound drivers. Traffic is steady through the day, with trucks and some school buses. The arborist plans to use an elevating work platform (EWP), a chipper and a tipper.

The traffic company is booked with a supervisor, two controllers and a vehicle. Whether a truck-mounted attenuator (TMA) is needed depends on the TGS and the road authority's requirements for the speed, volume and exposure; in this example the TGS calls for one behind the work area in the closed lane. Our guide to truck-mounted attenuators explains when they are required.

Why 80 km/h changes everything: an example stopping calculation

Drivers need distance to see a controller, decide and stop. The figures below are an illustrative physics calculation, not design values. Design distances come from the TGS, AS 1742.3, the AGTTM and the state's supplement.

Assume a 2-second perception and reaction time and a steady braking deceleration of 4.4 m/s² (a moderate value chosen for illustration).

The method: reaction distance is speed × 2 seconds; braking distance is speed² ÷ (2 × 4.4). At 80 km/h, 22.2² ÷ 8.8 is about 56 metres. Halving speed roughly quarters the braking distance. That is why the TGS in this example pairs the closure with a reduced temporary speed limit and places the controllers so that drivers coming round the bend can see them well before they need to stop. You can try your own numbers with the free stopping distance calculator, and our article on stopping sight distance at work zones explains the physics behind sign spacing.

The plan: closure for routine work, holds for the drop zone

The arborist and the traffic planner walk the site together and split the job into two kinds of activity:

The arborist defines the drop zone for each cut, including bounce and roll, and the supervisor confirms whether a hold is needed. Holds are kept short, and if the approval sets a maximum hold time, the cuts are planned to fit it. Long queues at 80 km/h create their own end-of-queue risk, which our end-of-queue management guide covers.

Set-up order and briefing

1. Pre-start, SWMS sign-on and radio check. Work next to a road used by traffic is high-risk construction work, so a SWMS is required. The arborist's crew signs the traffic SWMS or a combined briefing, and the traffic crew is briefed on the arborist's exclusion zones.
2. Advance warning signs in both directions, at the positions on the TGS, starting with the approach from beyond the bend because it has the poorest sight distance.
3. Temporary speed limit signs and any covers on conflicting permanent signs, as the TGS and speed zone approval require.
4. Controller positions set where drivers can see them in time, each with an escape route that does not lead into the drop zone.
5. The taper and closure of the northbound lane and shoulder, with the TMA positioned per the TGS.
6. EWP and chipper move in only after the closure is checked.
7. Supervisor walk-through and photo record before the first cut.

Briefing points specific to this job: the hold script, the drop zone for each stage, where controllers must never stand, who can call an emergency stop (anyone), what happens if wind picks up, and how to handle a heavy vehicle in the queue.

The hold script: radio calls for every cut

Every hold uses the same words. Consistency is what stops a cut going ahead with a car still in the lane.

1. Arborist to supervisor: "Ready for a hold, limb over the southbound lane."
2. Supervisor: "North end, south end, stop your traffic and give me last vehicles."
3. TC 1 (north): "North stopped, last through is a blue sedan."
4. TC 2 (south): "South stopped, last through is a white truck." Then, when the sedan passes: "Blue sedan through south."
5. Supervisor checks the lane visually: "Lane clear, both ends holding. Arborist, you're clear to cut."
6. Arborist after the cut: "Cut complete, nothing hanging."
7. Crew clears debris from the lane; the supervisor checks the surface.
8. Supervisor: "Road clear. South end, release first." Normal stop/slow resumes.

If anyone loses radio contact, the default is to hold, not to release. Agree a backup channel at the briefing and test it before the first hold.

What goes wrong in this example, and the fix

• Wind increases mid-morning. The arborist widens the drop zone for the upper trunk. The supervisor confirms the controllers' positions are still outside it and moves TC 2 further back, adjusting the advance signs to match the TGS. Any change outside what the TGS allows goes to the designer; our article on changing a TGS on site covers who can approve it.
• A truck in the queue cannot see the controller because a parked tipper blocks the line of sight. The tipper is moved into the closed area, behind the TMA.
• A small branch lands in the open lane during routine work that was not meant to need a hold. Traffic is stopped, the branch is removed, and the arborist reassesses: the remaining limbs on that side are moved to the hold list.
• A driver gets out of their car to argue during a hold. The controller stays calm, explains the hold will be short, and calls the supervisor if it escalates. Nobody leaves their station to deal with it.

Common mistakes on roadside tree jobs

• Treating the closure as enough. A closed shoulder does nothing if a limb can fall or roll into the open lane. Every cut whose drop zone reaches traffic needs a hold.
• Controllers standing in the drop zone. The best place to see traffic is not always a safe place when a trunk section is coming down. Check each station against each stage of the job.
• Starting a cut on a nod. Hand signals and assumptions between the arborist and the traffic crew are how a car ends up under a falling limb. Use the radio script every time.
• Releasing before the debris check. Bark, twigs and sawdust on an 80 km/h road surface can cause a motorcycle to lose control. Look before you release.
• Ignoring the queue. Repeated holds on a fast road build queues back towards the bend. Watch the end of the queue and tell the supervisor if it approaches the advance warning signs.
• Chipper pointed at the road. Discharge and flying chips should be directed away from traffic and the controllers.

Pack-down and the shift record

After clean-up, the supervisor walks the lane for leaves, bark and sawdust, which can be slippery, and the arborist confirms the stump area is safe. Pack-down runs in reverse: the closure and TMA come out, then the speed signs and covers, then the advance warning from the inside out, so drivers never meet signs for a closure that has gone.

In NSW, Transport for NSW's TS 05492 Traffic Control at Work Sites replaced the TCAWS manual on 25 June 2026, so check which document the project specifies with Transport for NSW. The national guide is available from Austroads, and WHS requirements for high-risk construction work are on SafeWork NSW.

Next steps

Before your next tree job on a fast road, walk the site with the arborist, list every cut whose drop zone reaches the lane, and write the hold script into the briefing. If you run a traffic control company, TrafWise records SWMS sign-ons, pre-starts and signed digital dockets for each shift so the hold log has a home.