This map shows the section of the M4 that is frequently congested, and that would be bypassed if plans for a 14-mile relief road went ahead.
The Welsh government has long pushed for a relief road in this area. Plans were shelved in 2009 after the projected cost of the project rose to £1 billion.
More top news
A Royal Marine from Northern Ireland who built explosives for an Irish republican paramilitary group had 43 hides, a court has heard.
A gay man has spoken of pain he suffered as a young boy when doctors gave him chemicals and electric shocks in attempt to 'cure' him.
Showers in the north tonight, elsewhere mostly dry.