Roadwork sign spacing decides how much warning a driver gets before a lane closure, a shift or a traffic controller. Too close and drivers brake late; too far and the message is forgotten before they reach the work. This builder places every advance sign at the distance the current rules require, draws the approach and gives you the taper, cones and clearances that go with it.
In NSW the rules come from Transport for NSW's TS 05492 Traffic Control at Work Sites, which replaced the TCAWS manual on 25 June 2026. In Queensland they come from QGTTM Part 3, TMR's supplement to the Austroads guide. The two states give different answers on the same road, so the builder asks for the state first.
How roadwork sign spacing works in NSW
NSW spacing is built on Dimension D: the speed of the zone drivers are in before a point, written in metres. On an 80 km/h road, D is 80 m.
- Multiple advance signs: the sign nearest the work goes D before the start of the taper or diversion. Each sign further upstream goes another D back.
- A single advance sign: D back at 60 km/h or less, 2D back at 70 km/h or more.
- Dual sign arrangements and multi-message signs count as multiple signs, so they use D.
D lags one zone behind. With zones of 100, 80, 60 and 40 km/h, the D values are 100, 100, 80 and 60 m, because drivers entering a new zone are still travelling at the speed of the one before. The builder applies this to every gap: a gap inside the 60 km/h zone after an 80 km/h zone uses D = 80 m. Where the designer judges that drivers won't slow down, they can use the permanent speed for D throughout; tick that box to see the difference.
The same lag applies to tapers. Table 74 is read at the preceding speed zone, so a merge in a 60 km/h zone that follows an 80 km/h zone uses the 80 km/h row: 130 m, not 60 m.
Queensland sign spacing and the 200 m rule
QGTTM Part 3 Table 2.2 sets the spacing by speed:
| Speed | Spacing between signs | Single advance sign |
|---|---|---|
| 55 km/h or less | 15 m | 30 m |
| 56 to 65 km/h | 45 m | 90 m |
| 66 km/h or more | equal to the speed (80 km/h = 80 m) | double the speed |
The primary sign goes that spacing from the worksite or taper, and later signs follow at the same spacing. The 200 m rule changes which speed you read: for the first 200 m after a speed limit change, use the higher speed. If a spacing is only partly inside that 200 m, the higher speed still applies to all of it. The builder repeats the calculation until every spacing is settled, so signs just after a speed change automatically get the longer gap.
Two Queensland points the builder flags rather than calculates. Table 2.2 doesn't set the distance between a traffic controller and the traffic control sign (that comes from AGTTM Part 7), and QLD taper lengths come from AGTTM Part 3, so type the taper from your TGS.
Speed zones, tapers and devices
Each temporary speed zone you add puts a speed sign in the list. The builder then checks how long each zone is on the layout:
| NSW zone | Minimum length | Source |
|---|---|---|
| Under 40 km/h work zone | 100 m (max 200 m) | Table 27 |
| 40 km/h work zone | 100 m (max 500 m) | Table 27 |
| 50 or 60 km/h work zone | 150 m | Table 27 |
| 70 km/h work zone | 200 m | Table 27 |
| 80 or 90 km/h work zone | 500 m | Table 27 |
| 50 or 60 km/h transition zone | 150 m | Table 28 |
| 80 or 90 km/h transition zone | 300 m | Table 28 |
With Stretch speed zones ticked, a speed sign moves further upstream when D spacing alone would leave its zone too short, and the gap is marked "stretched". The work zone length counts from its speed sign to the end of the work area.
At the speed where the devices sit, the builder also gives:
- the taper length (Table 74) and how many cones it takes at the maximum spacing (Table 50)
- the maximum cone spacing along the work
- edge clearance for cones, barrier boards and safety barrier (Table 49)
- the minimum lane width past the work, plus 0.5 m on curves under 250 m radius (Table 18)
- the lateral clearance for workers on foot (Table 81)
- the 30 m safety buffer before the work area
For cone spacing and counts in more detail, see our guide to traffic cone spacing.
A worked example
A crew is closing the left lane of a two-lane road with an 80 km/h limit in NSW. The TGS drops traffic to 60 km/h for a 100 m work area. The signs, in the order drivers meet them, are ROADWORK AHEAD, the 60 km/h speed sign, LANE CLOSED and END OF LANE.
Working back from the start of the taper:
- END OF LANE sits in the 60 km/h zone, which follows the 80 zone, so D = 80 m. It goes 80 m before the taper.
- LANE CLOSED is another 80 m back: 160 m.
- The 60 km/h sign is another 80 m back: 240 m. The 60 zone is then 240 + 100 = 340 m long, comfortably over the 150 m minimum.
- ROADWORK AHEAD is in the 80 km/h zone, so D = 80 m again: 320 m.
The merge taper is read at 80 km/h (the preceding zone): 130 m. At 60 km/h, cones in a merge taper can be up to 9 m apart, so the taper takes 16 cones, and cones along the work up to 12 m apart. Cones sit at least 0.5 m from the traffic lane, the open lane must be at least 3.0 m wide, and each 80 m gap may be set out anywhere from 72 m to 100 m under Table 88.
In Queensland the same road gives the same distances here, because every gap sits within 200 m of the 60 km/h sign and so uses the 80 km/h spacing of 80 m. On a 60 km/h road with a single sign, though, NSW puts it 60 m out and Queensland 90 m out.
Tolerances and changes on site
Signs can't always go exactly where the TGS shows them. In NSW, Table 88 lets a sign, taper or marking sit 10% short of to 25% beyond the distance on the TGS, and cone spacing up to 10% wider but not narrower. The builder shows each sign's band. These values were rebuilt from the PDF during our research, so check them against your copy.
The tolerances don't apply where the TGS gives a minimum, maximum or range. Every sign moved from its drawn position must be marked and initialled on the site copy of the TGS with the name of the person who moved it. Anything outside tolerance needs the PWZ-qualified designer. To check a set-up against the TGS, use the set-up tolerance check, and read changing a TGS on site for who can approve what.
Stop/slow and queues
For shuttle flow the builder measures from the traffic controller instead of the taper. PREPARE TO STOP signs are different: in both states the primary sign is placed back from the predicted end of the queue, not the controller. Plan those with the end-of-queue planner, and check the controller can be seen with the sight distance check.
When to get professional advice
This is a planning aid, not a traffic guidance scheme. Side roads, curves, crests and site constraints all change a layout, and the approved TGS always decides. Our guides to lane closure traffic plans and reading a TGS explain how the pieces fit. Victorian, WA and SA tables aren't loaded yet, so for those states the builder says so and points you to your TGS.