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
Former Newsnight presenter Jeremy Paxman has said he no longer watches the programme but revealed he's a fan of dating show Take Me Out
Prince Harry will miss the birth of his new niece or nephew as he has flown back to Australia.
Myleene Klass is set to shock Countdown fans by giving a naughty eight-letter word as her answer on tonight's show.