The La Son-Tuy Loan Expressway, which connects Thua Thien-Hue Province and Da Nang City and runs through the Bach Ma National Park, is undergoing pre-acceptance testing before opening this June. 

The La Son-Tuy Loan expressway, spanning 77 kilometers with four lanes, began construction in 2015. It has a total investment cost of VND11.5 trillion ($498.2 million) and was expected to be completed in 2018. Work was delayed, however, due to land clearance and weather issues.

After six years of construction, the 66 kilometer-long La Son-Hoa Lien section is near completion, while the 11.5 kilometer-long Hoa Lien-Tuy Loan section would remain a part of the 1A Highway. HCMC Road Project Management Committee said the new road should be operational this June once approved by the State Council for Pre-acceptance Testing.

A 11.5 kilometer section of the expressway runs through Bach Ma National Park. Over 25 hectares of woodland have had to be converted for the project.

This section has been found to affect the park's ecosystem, which hosts dozens of avian, mammalian, amphibian and reptilian species.

The expressway has a total 36 bridges and tunnels for animals to cross through.

Mui Trau Tunnel in the Ba Na-Nui Chua forest area, spanning 1.3 kilometers, cost around VND1.5 trillion.

Part of Mui Trau Tunnel's ventilation system.

Commuters in Da Nang and neighboring Quang Nam Province have begun using Mui Trau Tunnel to access Thua Thien-Hue, known for the former citadel Hue.

An employee of Son Hai, one of the investor companies, clears dust from a section running through Nam Dong District.

Multiple access roads serve Huong Phu Commune, Nam Dong District.

Warning signs have been erected along the expressway.

The HCMC Road Project Management Committee have sealed off a section in Huong Phu and the northern part of Mui Trau Tunnel, though some locals still gain access to unauthorized areas.

After it becomes operational, the La Son-Tuy Loan expressway would connect with the Da Nang-Quang Ngai and Cam Lo-La Son expressways, which are still under construction and will link with the central provinces of Quang Ngai and Quang Tri.