An open day will be held at the A477 Nash Fingerpost to Bangeston site offices on Wednesday, for local residents to find out more information on the developments.
Construction on the £3.725 million improvement started in March and is expected to take 18 months to complete.
Representatives of the Welsh Assembly Government and its consultants, Parsons Brinckerhoff and TACP, and the contractor Mowlem Civil Engineering will be available to explain the proposals and answer questions.
The open day will be at the site offices, between 10 am and 5.30 pm, which is on the north side of the trunk road, opposite Pembrokeshire Garden Centre. It will be signposted on the day for visitors.