Letting an Ambulance Through Stop/Slow: A Step-by-Step Radio Sequence

Letting an emergency vehicle through stop/slow safely means clearing the shuttle lane first, then releasing it, never waving it into oncoming traffic. A short radio sequence does the work: alert, hold, confirm clear, release, confirm through, resume. Brief the calls at the pre-start so both ends and the works crew act in seconds, not minutes.

An ambulance, fire truck or police car arriving with lights and sirens is a high-pressure moment. Drivers in the queue pull over unpredictably, the works crew may not hear the siren over plant noise, and the controller at the near end feels pressure to release immediately. This guide gives a step-by-step sequence, standard radio calls, a worked example and a printable card. It is general guidance: your traffic guidance scheme (TGS), company procedure and state rules come first. For planning emergency access at the design stage, see emergency vehicle access through roadworks.

Why you can't just wave it through

In stop/slow, one lane carries traffic in both directions in turns. If the controller at the near end releases an ambulance while the other end has released traffic, they meet head-on in the shuttle lane, possibly beside an open excavation. The emergency vehicle's lights and sirens don't change that geometry.

The priorities, in order:

1. Nobody gets hurt, including the crew and the emergency crew.
2. The shuttle lane is clear before the emergency vehicle enters it.
3. The emergency vehicle gets through as quickly as that allows.

Usually, a well-run crew can clear the lane in the time it takes the ambulance to reach the front of the queue. The sequence below is designed to make that happen.

The radio sequence, step by step

Use your company's call signs and wording. The structure matters more than the exact words.

1. Alert (whoever sees or hears it first). "Emergency, emergency. Ambulance approaching TC 1 end, northbound, lights and sirens." Saying the direction and which end tells everyone who has to act.
2. Hold (far end). The far end stops any further traffic entering the shuttle lane and replies: "TC 2 holding. Last vehicle in is a blue van."
3. Stop plant (supervisor or works crew). "Works crew, stop plant, keep clear of the lane." Plant stops moving, and nobody steps into the lane.
4. Clear (near end watches). The near end watches the last vehicle called arrive and pass. "Blue van through at TC 1."
5. Confirm lane clear (supervisor or far end). "Lane clear, plant stopped, TC 2 still holding." Nobody releases until this call is made.
6. Release (near end). The near end guides the emergency vehicle through, keeping clear of its path. "Ambulance released from TC 1."
7. Confirm through (far end). "Ambulance through TC 2." The far end still holds its traffic until this call.
8. Resume. The supervisor decides how to resume, usually by releasing the end that has waited longest. "Resume normal, TC 2 release first."

Handling the queue while the lane clears

The queue at the near end is often the slowest part. Drivers try to pull over for the siren, sometimes into the shuttle lane or towards the work area.

• Use clear hand signals to keep queued vehicles where they are, or to move them over only into space the TGS treats as available, such as a sealed shoulder.
• Never direct vehicles into the work area, into a closed lane or towards an excavation to make room.
• Don't ask anyone to reverse. Reversing in a queue is a common way to cause a second crash.
• Speak briefly to drivers if needed: "Stay where you are please, I'll bring the ambulance through."
• Watch the emergency vehicle's path. It may come up the outside of the queue. Make sure your station and escape route are not in that path.

If the emergency vehicle arrives at the far end instead, everything mirrors: the far end alerts, the near end holds.

Example scenario: ambulance at a two-way stop/slow

Here is how this plays out on a typical job. The site is a two-lane road with a posted 60 km/h limit, with stop/slow controlling a single lane past a trench for a water main. The single-lane section is roughly a short block long. TC 1 is at the western end, TC 2 at the eastern end, and the supervisor is near the work area. An excavator is loading a truck beside the lane.

1. 9:12 am. TC 1 hears a siren behind the western queue of six cars. TC 1 calls: "Emergency, emergency. Ambulance approaching TC 1, eastbound, lights and sirens."
2. 9:12 am. TC 2 has just released three vehicles westbound. TC 2 turns to STOP, holds the next car and replies: "TC 2 holding. Last in is a white ute with a trailer."
3. 9:12 am. The supervisor calls: "Excavator stop, crew keep clear of the lane," and signals the operator, who stops and lowers the bucket.
4. 9:13 am. In TC 1's queue, the second car starts to pull right towards the shuttle lane to let the ambulance pass. TC 1 signals it to stay put and says: "Stay there please, I'll bring the ambulance through."
5. 9:13 am. The white ute with trailer passes TC 1. TC 1 calls: "White ute and trailer through at TC 1."
6. 9:13 am. The supervisor walks the edge of the lane with a view of the whole section and calls: "Lane clear, excavator stopped, TC 2 holding."
7. 9:14 am. The ambulance reaches the front of the queue on the outside. TC 1, standing on the footpath clear of its path, waves it through: "Ambulance released from TC 1."
8. 9:14 am. TC 2 sees it pass: "Ambulance through TC 2." The supervisor calls: "Resume normal, TC 2 release first, their queue's been waiting."
9. Record. The supervisor notes in the site diary: time alerted, time through, direction, vehicle type, the queued car that moved, and that the excavator stopped. At the debrief, the crew agrees to remind the operator to watch for the supervisor's signal, as he hadn't heard the siren over the engine.

From siren to through took around two minutes, most of it waiting for the last vehicle to clear, which is exactly as it should be.

Emergency vehicle printable card

Print this for each controller and the supervisor.

Special cases: arriving at the site, multiple vehicles, radio failure

The emergency vehicle is coming to your site. If the call is for someone on the crew or a crash at the zone, the emergency crew may need to stop inside the work area. Hold both ends, stop plant, and have the supervisor meet them and guide them in. The crash in work zone response guide covers the wider response.

More than one emergency vehicle. Fire and police often travel in convoy or close behind an ambulance. Don't resume after the first one if you can still hear sirens. Ask the far end to keep holding until you confirm no more are coming.

Large appliances. Fire trucks need more width and a wider turning path. If the shuttle lane is narrow, check whether any delineation needs to move, but only as the TGS allows, and only after the lane is clear.

Radios fail. Both ends hold traffic on STOP. The near end does not release the emergency vehicle until the supervisor or the far end has visibly confirmed the lane is clear, by agreed hand signal or in person. The radio communication guide covers fallback arrangements.

Long-term works near hospitals or stations. Where the job runs near a hospital, ambulance station or fire station, the planner should consider notifying emergency services and including a specific procedure in the plan. Ask about it at mobilisation.

Recording and debriefing

Every emergency vehicle movement through the zone is worth a line in the site diary: time alerted, time through, direction, vehicle type and anything that slowed it or went wrong. If a queued driver did something dangerous, or the lane wasn't clear when the vehicle arrived at the front, treat it as a near miss and report it. Debrief at the next break while details are fresh. Useful debrief questions are short: Did everyone hear the alert? How long did the lane take to clear? Did the plant stop when asked? Did any queued driver move into a dangerous spot? What one thing would make it faster and safer next time? Feed the answer into tomorrow's pre-start.

For road rules on emergency vehicles, check your state authority, such as Transport for NSW or VicRoads. National guidance on temporary traffic management is in the AGTTM from Austroads.

Next steps

Add the emergency sequence to your pre-start, and run it once as a dry rehearsal with both ends and the plant operator on the first day at a new site. If you're planning cycle times on a busy road, the free stop/slow cycle planner helps you estimate how long the lane takes to clear.