15 Traffic Control Set-Up Mistakes Supervisors See Every Week (and the Fix for Each)

The traffic control set up mistakes supervisors see most often are signs out of sequence, missing sign covers, devices hidden by parked vehicles, tapers built from memory and escape paths blocked by the crew's own ute. Most come from rushing the set-up order, and most are caught by checking against the TGS and doing a slow drive-through.

This guide lists 15 mistakes that turn up week after week, why each one matters and the practical fix, then walks through an example morning where three of them happen on the same job. It is general guidance, not engineering or legal advice. The traffic guidance scheme (TGS) must be prepared by a suitably qualified person, and the crew's job is to build exactly what it shows. If you need a refresher on reading one, start with how to read a traffic guidance scheme.

Why set-up mistakes keep happening

Set-up is the busiest and most exposed part of the shift. The crew is carrying signs along a live road, often before the sun is fully up, with a client waiting to start. Experienced crews are not immune: in fact, familiarity is the main cause. A controller who has set up a hundred shoulder closures can place signs by habit, and habit does not know that this road has a crest, a driveway or a different speed limit.

The pattern supervisors see is consistent:

• The briefing was short, so the crew did not know where this TGS differs from the usual layout.
• Set-up order was skipped, usually by placing the work area cones first because the client wanted to start.
• Nobody checked from the driver's seat, so problems visible at speed were never seen.
• Corrections were not recorded, so the next inspection had no baseline.

Mistakes 1–5: signs and sequence

1. Setting up out of order. Cones and the work area go out before the advance warning signs, so for ten minutes drivers meet a lane full of workers with no warning. Fix: set up in the order drivers meet the devices, starting with the first advance sign, and pack down in reverse. Brief the order at the pre-start.

2. Signs placed from memory, not the TGS. Spacing and sequence follow last week's job. Fix: the implementer walks the TGS against the road and pace-checks or measures the positions the TGS specifies for this speed and road type. Distances come from the TGS, built from AS 1742.3 and the state's manual, not from habit.

3. Conflicting permanent signs left uncovered. A permanent speed sign or lane arrow contradicts the temporary layout. Fix: the TGS should show which permanent signs to cover. Cover them fully and remove the covers at pack-down. See covering permanent signs at roadworks.

4. Speed signs that don't match the approval. A reduced speed sign goes up without the approval the job needs, or the wrong value is used. Fix: confirm at the pre-start what temporary speed limit is approved and where it starts and ends. Check the speed sign repeats and the end sign.

5. Signs left up after the hazard has gone. "Workers ahead" stays up during a lunch break with nobody on the road, or overnight with no hazard. Drivers learn to ignore signs. Fix: show signs only while the hazard they describe exists. Turn, cover or remove them otherwise, as the TGS and after-care arrangements allow.

Mistakes 6–10: visibility, devices and stability

6. Signs hidden by parked vehicles or vegetation. The ute, a parked truck or an overhanging branch hides the first sign. Fix: check every sign from the driver's approach, not from the footpath. Re-park or relocate within what the TGS allows.

7. Signs on a crest or just past a bend. The sign sits exactly where the TGS distance put it, but drivers cannot see it in time. Fix: the TGS should account for sight distance. If the site does not match the plan, stop and contact the TGS author or supervisor rather than inventing a new position. The stopping sight distance at work zones guide explains why this matters.

8. Tapers with gaps or uneven spacing. Cones blown over, missing or bunched together so the line drivers follow is unclear. Fix: build the taper to the spacing the TGS shows, then look along it from the approach. Gaps should be obvious from the driver's seat.

9. Unstable signs and stands. Sign stands without weights, or with sandbags missing, fall over in the first gust or truck wash. Fix: weight every stand as the supplier and procedure require, and recheck after weather changes or heavy vehicle traffic.

10. Dirty, faded or damaged devices. A sign face that reflects poorly at night or a cone with a torn sleeve. Fix: reject damaged devices at the depot check, and tag them out of service on the equipment register rather than leaving them in the ute.

Mistakes 11–15: people, vehicles and escape

11. The crew's ute parked in the escape path. The controller's escape route runs straight into the tray of the ute. Fix: park vehicles where the TGS or procedure shows, and walk each controller's escape path before traffic is stopped.

12. Controllers standing in the live lane to be seen. Usually a sign the station is poorly placed. Fix: improve the station position within the TGS. Our stop/slow bat technique guide covers station checks.

13. No safe pedestrian route. The footpath is closed by a sign stand with no alternative, or the alternative sends people onto the road. Fix: build the pedestrian route as the TGS shows before closing the footpath, and check it with a pram or wheelchair user in mind.

14. Work area spreading past the delineation. Plant and materials creep into the buffer or the live lane through the shift. Fix: brief the works crew on where the work area ends. Supervisors check at every inspection and pull the work back.

15. Radio checks skipped. Controllers discover at the first release that the radios are on different channels. Fix: radio check every position before the first stop, and agree a fallback if contact drops.

Example scenario: three mistakes on one morning

Here is how this plays out on a typical job. The site is a two-lane suburban road with a posted 60 km/h limit. The TGS shows a shoulder and lane closure with stop/slow at each end while a drainage crew works in one lane. The crew is a supervisor and two traffic controllers, TC 1 and TC 2.

1. Pre-start, 6:15 am. The supervisor reads the TGS aloud and notes that, unlike the usual layout, there is a driveway inside the advance warning area on the eastern approach. The client's foreman asks if cones can go out first so the excavator can unload. The supervisor says no: advance signs first.
2. Set-up, 6:30 am. TC 2 sets up the eastern approach and places the first sign at the usual position, which turns out to be just past a gentle bend (mistake 7). TC 1 parks the ute behind the western station, right in the escape path (mistake 11).
3. Drive-through, 6:55 am. The supervisor drives both approaches before releasing any traffic. Coming round the bend, the first eastern sign appears late. On the western approach, the controller's position looks fine, but on foot the escape path is clearly blocked by the ute.
4. Corrections. The eastern sign is moved to the position the TGS actually shows, which is before the bend; TC 2 had placed it from habit, not from the plan. The ute is moved forward into the closed lane where the TGS shows the work vehicle.
5. Mid-morning inspection, 9:30 am. The supervisor finds a permanent 60 sign inside the closure uncovered while the approved temporary speed is lower (mistake 3). It was missed because the cover bag was still in the other ute. It is covered and the near-miss of a confusing message noted.
6. Records. The inspection record shows the start-of-shift check at 6:55 am with two corrections, and the 9:30 am check with one. Each entry has the time, the item, the fix and who did it.

The lesson for the crew is simple. None of these were knowledge gaps. All three came from habit and haste, and all three were caught because the supervisor checked from the driver's position and against the plan.

A printable set-up check sheet

Use this as a quick check after set-up and before releasing traffic. Tick each line and initial it. It does not replace the project's inspection form.

How supervisors catch mistakes before they matter

The checks that work are boring and consistent:

• Brief the differences, not the basics. At the pre-start, spend your time on what is unusual about this site: the driveway, the bend, the school, the bus stop.
• Drive it, then walk it. A drive-through shows what drivers see. A walk shows escape paths, trip hazards and pedestrian routes.
• Inspect at the right times. In NSW practice, work-site traffic control is inspected at the start and end of every shift and at suitable intervals during it, plus weekly and after-care inspections, recorded on the project's forms. Other states have similar expectations, so check your project's requirements.
• Record honestly. An inspection record that shows corrections is more credible than one that is always perfect.
• Close the loop. If the same mistake keeps turning up, raise it at a traffic control toolbox talk rather than correcting it quietly every week.

For the standards behind the layouts, check the current documents with Transport for NSW (which replaced the TCAWS manual with TS 05492 in June 2026) and Austroads for the AGTTM. Your project may still specify an older document, so confirm which one applies.

Next steps

Print the check sheet, brief it at your next pre-start and ask each controller to name one mistake they have seen this month. If you run a crew, a digital pre-start and inspection record in an app such as TrafWise makes corrections and times easier to capture on the road, with less paperwork to chase at the end of the week.