The source said the construction of the road under a part of the Morchit-Saphan Mai-Kukot elevated railway is 91 per cent complete and it would be ready for traffic in late December.
The new road, built by the MRTA, has two lanes in each direction.
Motorists heading to Lam Lukka in Pathum Thani can enter the new road by making a turn on the inbound Phaholyothin before the Kor Por Or Intersection near the Bangkok Gate landmark.
At the Kukot police station they should make a U-turn to use the outbound Lam Lukka road.
Traffic from Lam Lukka can turn left to the new road at the Kukot police station and exit at the Kor Por Or Intersection to avoid traffic congestion on the Lam Lukka Road near the Thupa Temee Stadium.