Every roadworks layout is built on the assumption that drivers will follow it. An incursion plan is what you have for the ones who do not, and it is the only part of the arrangement that assumes the signs were ignored.

Incursions are ordinary, not exceptional

Vehicles enter closed areas routinely: a driver misses the taper, follows the vehicle in front through a gap, is distracted at the wrong moment, is impaired, or deliberately uses the closed lane to get ahead of a queue. Treating incursion as a rare failure leads to layouts that have no answer for it. Treating it as a normal event that happens on most jobs leads to layouts built with somewhere for people to go.

Distance is what buys the time

Nothing about an incursion is fast enough to react to at close range. The protection is the space between the cone line and the people, because that space is what converts a vehicle entering the closure into a few seconds of warning rather than an immediate impact. Every metre of safety zone that is given up to storage, parking or convenience is taken directly out of that reaction time.

Escape routes go away from the road

Everyone working in the closure needs a direction to move that leads away from traffic, identified before work starts and kept clear as the job progresses. That last part is where it breaks down: routes get blocked by materials, by plant that arrived later, by an excavation that has been opened, or by a barrier put up for a different reason. An escape route that has to be checked is not a route; it has to be obvious and empty.

Somebody has to be watching upstream

People concentrating on a task do not see a vehicle coming, and the noise of plant removes the audible warning. On layouts where the consequence justifies it, a person whose only job is watching the approach — not working, not helping, watching — is what turns the buffer distance into a usable warning. That role needs an agreed alarm that is audible over the work and understood to mean move immediately without asking why.

What happens after

Once a vehicle has entered the closure the layout is compromised, whether or not anything was struck. Displaced cones leave a gap the next driver will use, a struck barrier may no longer perform, and the crew has just had a serious near miss. Stopping, accounting for everyone, restoring the layout properly before resuming, and recording it are all part of the response — and the record is what eventually justifies a better layout at that location.

For the space that buys the warning, see the safety zone. For what stops a vehicle rather than informing it, see what actually stops a vehicle.

Related standards

The standards below set the classification, testing and performance requirements behind the equipment used for this work.

• EN 1317 — Road Restraint Systems
• EN 13422 — Portable Warning Devices and Delineators
• EN ISO 20471 — High-Visibility Clothing

Frequently asked questions