Announcing a measure you may have to withdraw: a practical guide to precaution under technical uncertainty

The structural engineer is still running the numbers, the contractor starts on Friday night and the hauliers in the region are planning next week’s trips. Do you announce the restriction now, at the risk of having to withdraw it? Or do you wait for the result, at the risk of announcing a ban on Sunday evening that takes effect on Monday morning?

Rijkswaterstaat, the Dutch national infrastructure agency, faced exactly that choice at the end of September. On Wednesday 30 September it announced that the A6 viaduct at the Domineesweg in Urk would be subject to a 35 tonne weight restriction from 5 October. During major maintenance on the A6 motorway between the Ketelbrug and Urk, traffic in both directions runs on one half of the road, which loads the structure differently from normal. Heavy vehicles would be diverted via the N50 and N307 for a month. On Friday 2 October, a few hours before the works began, a second notice followed: the restriction would not go ahead. A recalculation had shown that the structure has sufficient load capacity.

Rijkswaterstaat itself wrote that it understood this was confusing for transport companies, and that the possible restriction had to be announced in advance because of the research tracks and planning deadlines involved. That is an honest explanation, and the decision to report early was defensible. Yet in a situation like this there is more to gain than understanding after the fact.

Why this will happen more often

The renewal programme for ageing infrastructure is making this type of decision routine. Structures from the 1960s and 1970s are being reassessed, inspected and temporarily loaded differently by works. Sometimes the outcome is firm. On the Houtribdijk (N307), the dam road between Lelystad and Enkhuizen, a 15 tonne weight limit and a 7.3 tonne axle load limit apply from 21 October, because the movable bridges at the Houtrib locks show cracks in the steel. That restriction may last for years. Hauliers will divert via the Afsluitdijk or via Amsterdam, which according to public broadcaster NOS costs almost an hour. One transport company that crosses the dam 500 to 800 times a week expects to need about twenty extra lorries a week for the same volume. In July the Merwedebrug on the A27 was closed to heavy goods vehicles overnight.

More often, the outcome is still open at the moment the outside world needs to know. In that case you are not communicating a measure but the chance of a measure. The usual toolkit (press release, yellow diversion signs, a letter to the trade association) is not designed for that. The six steps below are meant for road authorities, project teams and stakeholder managers who have to bring such a conditional measure into the open.

1. Say which type of measure it is

For the recipient it makes a great difference whether a restriction rests on established damage or on a calculation still in progress. Make that distinction in the first paragraph, not in a subordinate clause.

Established restriction. Damage or a capacity shortfall has been found. The measure is certain, only its duration is not. Example: the Houtribdijk.
Precautionary measure. There is reason for doubt, the investigation is ongoing, and the measure applies until the contrary is shown. Example: Urk.
Conditional announcement. The measure only takes effect if the investigation turns out unfavourably. The recipient needs to prepare, but does not have to change anything yet.

In the Urk case the notice did say “as a precaution”, but the headline and the thrust were those of a settled ban. The trade press reported it as fact. If you present a precaution as a fact, you later have to withdraw it as a mistake.

2. Publish the decision point

A transport planner can work with uncertainty as long as it is clear when it ends. So put three things in the announcement:

What the measure depends on (which calculation or inspection).
When the result will be known, with day and time.
Through which channel you will report it.

“On Friday at noon we will confirm whether the restriction takes effect on Monday” turns a surprise into an appointment. It makes a later withdrawal the conclusion of an announced process instead of a change of course.

3. Work back from the other party’s planning

In practice the notice period is set by your own programme: when the calculation is ready, when the contractor starts. The better question is how much time the hardest hit user needs. A haulier running abnormal loads, a livestock trader with fixed collection routes or a fish processor with daily deliveries plans days to weeks ahead, and sometimes needs permits for the diversion route.

Between the Urk announcement and the start date there were three working days. That is short for a month-long diversion. If you cannot extend that period, say so and offer something in return: a direct point of contact, help with permits, or a transition day without enforcement.

4. Prepare the withdrawal as a full scenario

Most communication plans contain one scenario: the measure takes effect. Write out the second scenario in advance, with the same care.

Same channels, same reach. Whoever received the announcement receives the withdrawal. That includes trade associations, municipalities, regional media and the parties that feed traffic information and navigation services.
Signs. Yellow signs already in place are covered or removed the same day. A sign left standing beats any press release.
The old notice. Correct the original publication visibly at the top and change the title. A notice that remains findable under its old headline will still be sending lorries on a detour weeks later.
One sender. Have the withdrawal come from the same person or the same desk as the announcement.

5. Explain what changed

“New technical calculations show that the structure has sufficient load capacity” is correct, but it raises the question why that was not known on Wednesday. A short, understandable explanation prevents people from inventing their own. What was the uncertainty? Which assumption was replaced by a measurement or a more refined model? Is there a remaining margin you are monitoring?

You do not need to publish a calculation report. Three sentences will do. They make the difference between “they did not know” and “they found out”.

6. Acknowledge what it has already cost

In two days, planners rerouted trips, called customers and rescheduled drivers. That is not damage in a legal sense, but it is work. Say so, thank people for it and keep the contact desk open for another week for anyone dealing with the consequences.

Also keep an internal record: which precautionary measures were announced, how many went ahead, how many were withdrawn and with what notice period. After a year you will have figures that make the next announcement credible. “Two out of three precautionary measures turned out not to be needed” is a sentence that helps a haulier judge what to do.

Four pitfalls

Waiting until you are sure. This is the most tempting and the worst. If you only report once the calculation is finished, an unfavourable result means announcing a ban that takes effect the next morning. Early and conditional beats late and certain.

Presenting the withdrawal as good news. For the road authority it is a windfall. For the planner who has just rearranged everything, it is the second change in three days. The tone of a withdrawal should be that of a correction, not of a success story.

Underestimating what it does to the next notice. Every measure that disappears without explanation makes the next one less credible. That is risky at a time when some restrictions, such as the one on the Houtribdijk, really will stay for years. The outside world must be able to tell the difference.

Letting precaution linger. The mirror image of Urk is the temporary restriction that is never lifted because the follow-up investigation has no owner. A precautionary measure without an end date or review point quietly becomes permanent, without anyone having decided that.

In closing

Rijkswaterstaat did two things well at Urk: it reported the possible restriction before the calculation was complete, and it acknowledged at withdrawal that this was confusing. What was missing lay in the form. The announcement read as a decision, there was no published decision point, and so the withdrawal came as a surprise.

As more bridges and viaducts are reassessed, communicating the chance of a measure is becoming a regular part of the job. That does not call for a larger communications team, but for a different standard sentence: not “from Monday the following applies”, but “on Friday at noon we will know whether it applies from Monday”. If you give your uncertainty a date, you are allowed to change your mind afterwards. We wrote earlier about the other side of this coin, being precise about postponement and cancellation; the principle is the same.