Overnight work begins on A12 south of Ipswich

But few motorists have seen the engineers at work because they are on site between 10pm and 6am every night in a bid to keep traffic disruption to a minimum.

Work has started on crash barriers near the Copdock Mill roundabout and will be continuing along the road until the spring.

A 40 mph speed limit has been introduced on the route to protect the overnight workers and because the road surface itself will be uneven for a time when work starts on the carriageways.

Average speed cameras have been set up, and will be switched on within the next two weeks in a bid to deter motorists from driving too fast.

A spokeswoman for the Highways Agency said the exact time the work would take depended on the weather over the winter.

She said: “We have said it should take about four months to complete the work, but if we get some bad weather that could push us back.

“The work has now got fully under way and there is a great deal happening overnight.”

The work has been scheduled to take place overnight to cause as little disruption as possible to the traffic using the road.

This has led some motorists to question whether anything is happening – because at busy times of the day there are no engineers to be seen.

A total of 10 miles of carriageway will be resurfaced during the four-month programme, which the Highways Agency says should significantly improve journeys on the road.

Highways Agency project manager Anna Graham said: “This is a multi-million pound scheme which is taking place to prolong the life of the carriageway.

“The work has been designed to improve the surface of the road and safety for road users, while minimising the need for future maintenance works in these locations.”

The agency is also resurfacing the A12 in south Essex between Ingatestone and the M25 junction at Brentwood.

Again this work is substantially being undertaken by teams of engineers working overnight to minimise disruption to traffic as much as possible.