How to Do a Drive-Through Inspection of Your Own Work Zone

A work zone drive-through inspection means driving each approach to your own site the way a road user would, with an observer calling out every sign, cone and controller as it appears. It shows what drivers actually see: late signs, confusing tapers, hidden controllers. Do it after set-up, after every change, and again after dark.

Walking the site checks positions. Driving it checks whether the layout works at speed. This guide sets out how to run a drive-through properly, what to look for on each pass, a worked example on a stop/slow job, and a log you can print. It is general guidance: the traffic guidance scheme (TGS) must be prepared by a suitably qualified person, and your project's inspection forms and state requirements come first.

Why drive it when you've already walked it

From the footpath, a sign three metres behind a parked car looks fine because you can see it from the side. From a car approaching at 60 km/h, it is invisible until the last moment. A drive-through answers questions a walk cannot:

• When does each sign first come into view, and is there enough time to read and react?
• Does the sequence of signs make sense in the order you pass them?
• Is the taper a clear line, or a scatter of cones?
• Can you see the traffic controller, and are they clearly separated from your lane?
• Does anything distract or dazzle: floodlights, beacons, a VMS board, the low sun?
• Where does the queue end, and can drivers see it in time? See end-of-queue management.

Before you start: roles, route and timing

Two people, two jobs. The driver drives, watches the road and stays legal. The observer holds the TGS, calls out each device as it appears and writes notes. One person cannot safely do both.

Plan the route. Cover every approach the TGS shows: both directions on the main road, plus side streets and driveways that feed into the zone. Know where you will turn around safely and legally before you set off.

Pick a realistic speed. Approach at a safe and legal speed that matches how traffic arrives, usually the posted or approved temporary speed where safe. Driving at a crawl gives you more time than real drivers have.

Use a normal vehicle view. Where possible, use a car or ute with a typical driver's eye height. If heavy vehicles are common on the road, a check from a higher seat can reveal different issues, but do the standard view first.

Tell the crew. Radio the controllers that you are doing a drive-through, so they treat you like any other vehicle and don't wave you through specially.

What to check on each pass

The observer works through the zone in the order the driver meets it.

1. Advance warning. Call out the moment each sign becomes readable. Note any that appear late, are hidden, twisted or dirty.
2. Speed signs. Check the value matches the approved temporary speed, and that conflicting permanent signs are covered.
3. Taper and delineation. Is the path obvious? Any gaps, fallen cones or confusing lines? Do old line markings fight the new path?
4. Controller stations. Can you see the controller early? Are they off the travel path with a clear escape route?
5. Work area. Are workers and plant inside the delineation? Is the buffer empty? Are site vehicles parked as the TGS shows?
6. Pedestrians and cyclists. Is the alternative route visible and usable? See pedestrian management at work sites.
7. End of works. Is there a clear end sign and speed restoration where the TGS shows one?
8. Return direction. Repeat everything in the opposite direction, and on each side street.

Example scenario: stop/slow on a rural road

Here is how this plays out on a typical job. The site is a two-lane rural road with a posted 100 km/h limit and a reduced temporary speed approved for the works. The TGS shows stop/slow at each end of a single-lane section where a crew is repairing a culvert. The crew is a supervisor, TC 1 at the northern station and TC 2 at the southern station.

1. 6:45 am, after set-up. The supervisor drives and a works crew leader observes with the TGS. The pair radio TC 1 and TC 2: "Drive-through starting, northbound, treat us as normal traffic."
2. Northbound pass. The first two signs are clear. The temporary speed sign is visible but a permanent 100 sign 50 metres later is uncovered. Finding noted.
3. At the southern station. TC 2 is visible from a long way back, but the sun is directly behind the station; for several seconds the observer cannot read the bat. Finding noted.
4. Southbound pass. All signs fine. The end-of-queue sign is placed for a short queue, but the observer notes that at the morning peak the queue could pass it.
5. Corrections, 7:05 am. The permanent sign is covered. For the sun, the supervisor checks the TGS: the station can move slightly within the allowed area so the controller is not directly in front of the sun. For the queue, TC 2 is briefed to radio when the queue reaches a marker and the supervisor will extend the end-of-queue warning as the TGS allows. See roadworks queue monitoring.
6. 7:15 am, second pass. Both directions checked again. All findings closed. Traffic released.
7. Afternoon. As the sun swings to the other side, the supervisor does another drive-through at the 2:30 pm inspection and finds TC 1 is now the one backlit.

The supervisor records each pass with time, direction, findings and fixes. The afternoon finding goes onto the toolbox talk for tomorrow, so both stations are planned for sun angle from the start.

Drive-through log template

Print one per shift. One line per pass.

Attach it to the project's inspection form or copy the findings across. The traffic control site diary guide covers what else to record during the shift.

Turning findings into fixes: correct, escalate or stop

Not every finding gets the same response. Sorting them quickly is what keeps the crew safe without holding the job up for every small issue. Use a simple decision table at the debrief straight after the pass.

A correction puts the site back to what the TGS shows. An escalation means the site and the plan don't match, and only a suitably qualified person should change the plan. A stop means the risk is immediate. Brief the crew on all three at the pre-start, so a controller who sees a "stop" issue knows they can call it.

After any correction or change, drive it again. A fix that looks right on foot can still fail from the driver's seat, and the second pass is your evidence that the finding was closed rather than just attended to.

Night drive-throughs

Night works need their own drive-through because almost everything looks different:

• Low beam first. Most drivers approach on low beam in urban areas. Check signs are readable with low beam only.
• Glare. Floodlights aimed at the work area can dazzle approaching drivers. Note any light that makes you squint and have it re-aimed.
• Beacons and ute lights. A cluster of flashing beacons can hide a controller rather than highlight them.
• Delineation. Check that cones and bollards reflect clearly, and that the path through the zone is obvious in the dark.
• Controllers. Night-rated hi-vis and an illuminated wand should make each controller stand out from the lighting around them.

Do the first night pass as soon as it is fully dark, not just at set-up in twilight.

Common drive-through mistakes

For current state guidance, check with Transport for NSW, Transport and Main Roads Queensland or your state road authority, and the AGTTM via Austroads.

Next steps

Make the drive-through a fixed line on your pre-start and inspection checklists, with the log attached. If you want a ready-made list to adapt, the free traffic control checklists include set-up and inspection items you can print and take on the drive.