HONG KONG, Oct. 24 (Xinhua) -- The first batch of cross-boundary vehicles left the Hong Kong Boundary Crossing Facilities on Wednesday to travel on the world's longest cross-sea bridge, the Hong Kong-Zhuhai-Macao Bridge.

The 55-km bridge connects China's Hong Kong Special Administrative Region (SAR) in the east and the Macao SAR and Zhuhai of southern Guangdong Province in the west.

After nine years of construction, the Hong Kong-Zhuhai-Macao Bridge officially opened to public traffic at 9:00 a.m. local time (0100 GMT) on Wednesday, as the first batch of travelers entered the service hall for customs clearance.

At 9:30 a.m. local time (0130 GMT), the first batch of cross-border buses full of passengers, along with other vehicles, hit the road on the bridge for Macao or Zhuhai on the other ends of the Y-shaped bridge.

Without the bridge, drivers from Hong Kong, which faces Zhuhai across the Lingding Channel, had to detour via several cities including Shenzhen and Dongguan to reach Zhuhai and other cities in the western part of Guangdong province.

Crossing the mega bridge is a bucket list experience for many residents. A Hong Kong resident surnamed Lee in his 70s was one of them. He got up early on Wednesday to take the first bus to ride on the bridge, only to catch a glimpse of the grand project.

The bridge will slash the road travel time from Hong Kong to Macao and Zhuhai remarkably.

A Hong Kong resident surnamed Wong works in Macao and has to commute between Hong Kong and Macao regularly. He usually takes ferries, as road travel would take about three hours.

But the new bus service via the bridge will take less than an hour and the ticket is cheaper, and he plans to take it as a key commuting alternative in the future, Wong said.

On the first day of operation, Secretary for Transport and Housing of the Hong Kong SAR government Frank Chan Fan came to work at the Hong Kong Boundary Crossing Facilities.

He said that on the first day, passengers are all very excited and trying to be the first to board the buses, to buy the tickets, and to be the first to exit the departure hall.

"The capacity of handling is going to increase in the years to come. There are roughly about 100 cross-boundary coaches from Hong Kong to the mainland on the first day and some 30,000 tourists will come over from the mainland to Hong Kong," he said.

The six-lane crossing is expected to further link a regional economic zone in the Guangdong-Hong Kong-Macao Greater Bay Area.

The bridge will be important for Hong Kong's economic growth, and will further boost cooperation between Hong Kong and the Pearl River Delta, said Fang Zhou, director of the Hong Kong-based One-Country-Two-Systems Research Institute.