The four-kilometre, Eastern Section of the bypass takes vehicles from the edge of Tai Po on Fanling Highway to a new town in Fanling North.
Officials said the route would save commuters around 10 minutes during peak hours.
Civil Engineering and Development Department chief engineer, Pakin Cheung, said operations were smooth.
“It’s Sunday, so most residents might have been testing the new bypass out, to head towards the urban areas in Kowloon. They benefited from using the bypass to reach the Fanling Highway quicker, he told RTHK.
“As for Monday, the first working day of the week, we expect the traffic to be busier, so motorists may need more time to get used to new entries and exits along the bypass.”
DAB lawmaker Yiu Ming, representing New Territories North, said drivers need to be careful about new signage, as some sections that used to allow drivers to change lanes now have solid lines.
A number of motorists who tried out the new route said they enjoyed the experience, but added there might need to be some adjustments.
One of them was a driver surnamed Man, who lives in Ping Che.
“The new road is quite good, but maybe it’s brand new so there are some rocks around. I find the signage to be clear,” he said.
“It saved some time, because you don’t need to go through the old routes that have a lot of traffic lights. So I very much look forward to the first working day, hopefully this bypass can help residents in the district.”
Other drivers said while they personally won’t use the bypass much for now, they believe it will be a very important route down the line when an influx of residents is expected later with the development of the Northern Metropolis.