Third tunnel excavation begins on Romania’s toughest motorway section through the Carpathians

The third of seven planned tunnels on the most difficult segment of the A1 motorway has entered excavation, as Romanian road authority CNAIR pushes ahead with one of the country’s largest infrastructure projects. Work on the Balota tunnel commenced on 13 June 2026, joining ongoing construction at the Robești and Boița 1 tunnels.

Three tunnels under excavation

The Boița-Cornetu section runs 31.33 kilometres through the Carpathian Mountains and links Transylvania with Muntenia. It includes seven tunnels totalling about five kilometres, plus 24 bridges and 24 viaducts that together span roughly eleven kilometres. The contract, worth 4.25 billion lei (excluding VAT), is funded by Romania’s Transport Programme.

“On site there are now 562 workers, 155 machines, and the physical stage for the entire section has reached 11.63%.”

Tunnel-by-tunnel progress

The Balota tunnel, 500 metres long, has seen the first 16 metres excavated and the exit portal is now being prepared. Robești (900 metres) is 36% complete, with excavation of both galleries finished and waterproofing and concreting next. Boița 1 consists of two galleries, 264 and 247 metres long, where 87 metres and 21 metres have been excavated respectively, lifting the physical stage to 17.17%.

Balota (500 m)0%

Robești (900 m)36%

Boița 1 (264/247 m)17.17%

Balota (500 m)

0 %

Robești (900 m)

36 %

Boița 1 (264/247 m)

17.17 %

Data from the article text

Workforce and equipment mobilised

A total of 562 workers and 155 machines are deployed across the site. The workforce numbers were disclosed by CNAIR’s director general alongside the latest progress figures. The presence of three active tunnel fronts underscores the scale of simultaneous activity on this mountain section.

Regulatory bottleneck

Despite the construction momentum, the next critical step lies outside the contractor’s control. The entire site requires a Revised Environmental Agreement from the Ministry of Environment, a document necessary to issue the construction permits for all remaining works.

“The critical step ahead is not up to the builder but to the permits: the works depend on the issuance of the Revised Environmental Agreement by the Ministry of Environment, a mandatory condition for the Construction Permits on the whole site.”

Once the environmental clearance is obtained, work can extend across the full 31.33‑kilometre corridor, advancing a motorway that is expected to sharply reduce travel times between western and southern Romania and lift the tonnage restrictions on the old DN7 road.