Commuters are set for traffic delays on their journeys into Bristol this week.

Roadworks have begun at the Three Lamps junction in Totterdown, where the A37 Wells Road and the A4 Bath Road converge.

Hold-ups are also likely further out on the A37 at Whitchurch, where a six-month project to repair a gas main is getting under way.

Work on the A4174 Avon ring road at the Hambrook roundabout is affecting traffic. Speed limits are likely to be in place until the end of January.

Meanwhile, the resurfacing work on the Avonmouth bridge on the M5, which is prompting many drivers to seek alternative routes, will continue until Christmas.

Traffic was delayed at the Three Lamps junction yesterday, when temporary lights were operating. These will also be in force next Sunday.

During the week, there will be changes to lane allocations, either allowing buses in the main traffic lane or cars in the bus lane.

The seven-week project is aimed at improving the road for buses and cyclists.

City council spokeswoman Katharine de Lisle said: "When the improvements are complete, buses coming inbound on the Wells Road will be able to bypass the lights using a 'give way' lane. It will be similar to the system in place at the Jacobs Wells roundabout."

The work on the A37 at Whitchurch is being carried out by Wales and West Utilities, which is digging up parts of the road to replace an ageing metal gas main with plastic pipes.

One lane of the dual carriageway will have to be closed and there will be temporary traffic lights on the junction of Wells Road and Wharnecliffe Gardens.

Work was due to start on Wednesday but there was no sign of the road being dug up yesterday.

The work forms part of a multi-million-pound, 30-year programme across Wales and the South West to replace metal pipes within 30 metres of buildings with plastic pipes that last more than 80 years.

Drivers in Bristol also faced diversions yesterday because the Portway was closed for safety checks on the rock face.

A section of the road between Cumberland Basin and Sylvan Way in Shirehampton was shut.

Annual checks are carried out to check the stability of the rocks.

City council structures engineer, Phil Lloyd, said: "Over the years the rock face has become a lot more stable, but there are always some loose rocks when we check – that's just the nature of it because there is always erosion.

"We have done a lot of work stabilising it with mesh and rock anchors – which are like long bolts – but it still needs checking regularly to make sure no rocks fall on to the ground below.

"I employ a team of rope access specialists who are also geotechnically qualified. They abseil down the rock face checking for loose rocks, which they remove and drop on to the road to be removed.

"They also remove vegetation growth, because although it sometimes helps to stabilise the rock, it can also cause problems because it breaks it up by growing in cracks."