A TGS tolerance check answers the implementer's question at the end of every set-up: is this out on the road the way the drawing says, and if not, is it close enough? Signs can't always go exactly where the TGS shows them. A driveway, a pole or a bus stop gets in the way, and the rules allow for that within limits. This checker compares each measured distance with the TGS, tells you whether it's inside those limits, and produces a signed audit sheet for the site file.
In NSW the limits are in Transport for NSW's TS 05492 Traffic Control at Work Sites (June 2026), section 14.11. Queensland uses AGTTM Part 6 with its own notes in QGTTM Part 3.
The NSW TGS tolerance rules
TS 05492 Table 88 sets how far a sign or device may sit from a distance given on the TGS:
| What you're checking | Allowed below the TGS value | Allowed above the TGS value |
|---|---|---|
| Position of a sign | 10% less | 25% more |
| Length of a taper | 10% less | 25% more |
| Length of a pavement marking | 10% less | 25% more |
| Spacing of cones and delineators | nil | 10% more |
Three conditions sit around the table:
- No tolerance where the TGS gives a minimum, maximum or range. If the drawing says "minimum 120 m", 119 m fails. Choose "a minimum" or "a maximum" on the card and the checker holds you to it.
- Road features. Going beyond tolerance at an intersection or median opening is allowed only with approval from the PWZ-qualified TGS designer.
- Every moved sign is recorded. Any sign location change must be marked and initialled on the TGS held on site, with the name of the person who made it.
These values were rebuilt from the PDF during our research, so check them against your copy before you rely on a borderline result.
Spacing, clearance and lane width
Some things on a set-up have a hard limit as well as a TGS value, and the checker tests both.
- Cone spacing may be up to 10% wider than the TGS, but never wider than the Table 50 maximum for its purpose and the speed where the cones are: 4 m on the approach to a traffic controller, 9 m in a merge taper at 60 or 70 km/h, 12 m at 80 km/h and above.
- Edge clearance from the traffic lane (Table 49): cones 0.5 m at 60 km/h or less and 1.0 m above; barrier boards and guideposts 1.0 m; safety barrier from 0.3 m up to 2.0 m at 90 km/h and above.
- Lane width past the work (Table 18): 3.0 m at 60 km/h or less, 3.2 m from 70 to 90 km/h, 3.4 m at 100 km/h and above, plus 0.5 m per lane on curves under 250 m radius, and 3.5 m for shuttle flow on a state road.
For more on how cone spacing is set, read our traffic cone spacing guide.
How to use the checker on site
- Fill in the site, TGS number, date and your name, and pick the speed limit where the devices are.
- Tap Quick-add: typical lane closure for a starting list, or add your own checks. The quick-add values come from the tables at that speed; replace each with the figure on your TGS.
- Measure each item with a wheel, tape or by pacing, and type what you got. The card turns green, orange or red as you type.
- Add a photo where it helps, such as a sign that had to move for a driveway. Photos are shrunk and kept in this browser only.
- Sign in the box and print the audit sheet, or save it as a PDF.
The result lists failing items first, then items to check, then passes. Under that it tells you which signs to mark and initial, which adjustments to note on the TGS, and what needs the designer.
A worked example
A lane closure on an 80 km/h road has a 60 km/h work zone. The TGS shows signs 80 m apart, a 130 m merge taper, cones 9 m apart in the taper and 12 m along the work, cones 0.5 m from the traffic lane and a 3.0 m open lane. The implementer measures:
| Check | TGS | Measured | Allowed | Result |
|---|---|---|---|---|
| ROADWORK AHEAD to next sign | 80 m | 95 m | 72 to 100 m | Pass: mark and initial |
| Next sign to LANE CLOSED | 80 m | 70 m | 72 to 100 m | Fail: 2 m too close |
| Merge taper | 130 m | 120 m | 117 to 162.5 m | Pass: record on TGS |
| Cones in the taper | 9 m | 10 m | 9 m (Table 50 cap) | Fail |
| Cones along the work | 12 m | 12 m | 12 m (Table 50 cap) | Pass |
| Cone edge clearance | 0.5 m | 0.4 m | at least 0.5 m | Fail |
| Open lane width | 3.0 m | 3.2 m | at least 3.0 m | Pass |
Three items fail. Moving one of those two signs to open the gap back to at least 72 m, adding cones in the taper and pulling the cone line back 0.1 m fixes all three without a TGS change. The ROADWORK AHEAD sign moved 15 m, which is inside the 25%, so its new position is marked and initialled on the site copy. If the lane closure couldn't be fixed within tolerance, work would stop, the site would be made safe, and the designer would issue an updated TGS.
Queensland and other states
Queensland's sign spacing tolerances are in AGTTM Part 6 Section 6.8, with a figure in QGTTM Part 3 that isn't reproduced here. Where the designer has already used a tolerance, the TGS should state the distance as a minimum or maximum so it isn't applied twice on site. The checker tests QLD lane widths (Table 2.5) and barrier clearance (Table 5.1), applies any minimum or maximum on the TGS, and asks you to compare other items with your TGS. For other states it applies only the TGS minimums and maximums.
Records and when to call the designer
The IMP-qualified person must make sure the TGS is set out as approved, with minor adjustments within tolerance recorded on the TGS and a signed copy on site. Anomalies in the TGS itself go back to the designer. The guides on changing a TGS on site and temporary traffic management audits explain who signs off what, and inspection photos covers what makes a useful photo record.
Planning the layout before you set it out? The sign layout builder gives each sign's distance and tolerance band, and the sight distance check covers the controller's position.