Objections to preliminary works ahead of the installation of average speed cameras on 136 miles of the A9 are to be expected.

This has been a controversial proposal since ministers announced their plans last summer. But it is misguided to suggest that the Scottish Government should not press ahead with the measure.

Opponents of the introduction of the cameras on sections of the road that are not dual carriageway have introduced a petition to the Scottish Parliament calling for a debate in the chamber and a moratorium while other options are considered.

The petitions committee is a very useful option to allow the public to introduce concerns to Holyrood. But the committee has to be used properly. Its function is not to stall the introduction of policy. If any of a government's actions could be stalled simply by submitting a petition, we would be lucky to see our representatives achieve anything at all.

That does not mean the policy should not be scrutinised. But, given that it is (or should be) a short-term measure, putting it on hold is potentially counterproductive. While the long-term plan is to dual all the remaining single carriageway sections of the notorious A9, this will not be finished until 2025 and work will not begin until next year at the earliest.

There is good evidence that average speed cameras save lives. The system introduced on the A77 in Ayrshire has cut fatal accidents by 46% and non-fatal but serious crashes by 35%.

Yet critics say the research on average speed cameras is flawed and does not apply to the A9. It is driver frustration and bad decisions that give the A9 its deadly reputation, they argue. Impatient drivers overtaking slow moving traffic are the culprits.

The group behind the petition (A9 Average Speed Cameras are not the Answer) claims average speeds on the A9 are well below the legal limit at 58mph. Therefore, average speeds cameras will not help.

If that evidence is sound then campaigners should come forward with it. It invites further analysis.

On the surface, the claim appears implausible. Whenever mobile speed cameras are deployed along the route they catch hundreds of speeding motorists.

In January, The Herald reported that one speed camera unit north of Dunblane had issued 4000 tickets in a year to drivers travelling at 70mph. So speeding on the road is plainly a problem.

It is vital cameras are there for the right reasons. Public support depends on this, and is weakened where cameras appear to be used to generate revenue rather than to improve safety.

But the frustration drivers experience, which leads to dangerous overtaking, may well be removed by the knowledge that average speed cameras are in operation anyway.

The long-term solution to safety on the A9 is widely acknowledged to be the introduction of dual carriageways along the road.

That cannot be achieved immediately so, in the meantime, average speed cameras are a welcome step towards short-term safety.