The A3 motorway () is a partially built motorway in Romania, planned to connect Bucharest with the Transylvania region and the north-western part of the country. It will be 596 km long and will run along the route: Ploiești, Brașov, Făgăraș, Sighișoara, Târgu Mureș, Cluj-Napoca, Zalău and Oradea, connecting with Hungary's M4 motorway near Borș.

As of July 2025, there are roughly in service: the Bucharest – Ploiești motorway (62.5 km), the Râșnov – Cristian segment (6.3 km), the Târgu Mureș – Nădășelu segment (117 km) and the Biharia – Borș segment (5.4 km).

In January 2015, the motorway section between Târgu Mureș – Câmpia Turzii was awarded for construction. It was divided into two larger segments, with a total of five lots, which sum up 51.8 km. By December 2021, all segments have been opened to traffic, with the exception of Chețani − Câmpia Turzii (15.7 km), of which contract was terminated in March that year.

Additional works on the Nădășelu – Borș section (approx. 157 km, in total) were auctioned between 2018 and 2019, with contracts awarded for the Biharia − Borș segment (5.4 km, near the border with Hungary) in December 2018, the Chiribiș − Biharia segment (28.6 km) in June 2020, and the Zimbor – Poarta Sălajului segment (12.2 km) on the same month. Several other segments are still pending to be awarded.

Furthermore, on the Comarnic − Brașov section (58.0 km), the 5.2 km segment between Comarnic South – Comarnic North has been re-tendered in August 2020.

Bucharest – Brașov section Bucharest – Brașov section Section Length Period of construction Contractor Total cost Financier Status Bucharest – Moara Vlăsiei 19.5 km May 2008 – August 2017 Impresa Pizzarotti and Tirrena Scavi 673.7 m lei State budget In service Moara Vlăsiei – Ploiești 43.0 km July 2007 – August 2012 Spedition UMB, Pa&Co Internațional, EuroConstruct Trading '98, Com-Axa 883.7 m lei State budget In service Ploiești – Comarnic 48.6 km 379.4 m euro (est.) Planned Comarnic – Brașov 58 km State budget One segment in service, the rest - planned

This motorway section (also called the "Snow Motorway") will cross the Carpathian Mountains along the Prahova Valley (the Comarnic – Brașov segment is considered the most difficult section to be built). It will also provide access to the future Terminal 2 of the Henri Coandă Airport and to the future Bucharest – Chișinău motorway, via the Ploiești South-East (Dumbrava) interchange.

It was split into three larger sections: the Bucharest – Ploiești section (62 km), the Ploiești – Comarnic section (48.6 km) and the Comarnic – Brașov section (58 km).

Bucharest – Ploiești section Work on the Bucharest – Ploiești section started on 15 March 2007 and was due to be completed by October 2012.

The first segment, between Bucharest – Moara Vlăsiei (19.5 km), was built as a six-lane set of carriageways to accommodate commuting and holiday surplus traffic. It was built by the Italian joint venture between Impresa Pizzarotti and Tirrena Scavi, while the second segment, between Moara Vlăsiei – Ploiești (43.0 km), was built by the Romanian companies Spedition UMB, Pa&Co Internațional and EuroConstruct Trading '98. Total construction cost of this section was estimated at 450 million euro.

The section between Bucharest Ring Road – Ploiești (55.5 km) was opened on 19 July 2012, while the rest of the section towards downtown Bucharest remained to be completed.

The Bucharest – Bucharest Ring Road segment (6.5 km) is part of the Bucharest – Moara Vlăsiei subsection and was built under separately awarded contracts, as the one with Impresa Pizzarotti was terminated. It starts with a roundabout at the junction between the Fabrica de Glucoză and the Petricani Street (near ), crosses over the Balta Saulei Lake, intersects the Gherghiței Street with a second roundabout (near ), then continues northbound, crossing over the CFR Line 800, the Popasului Street (in Voluntari, where it has a diamond interchange near ) and the Bucharest Ring Road, as well as the railroad again.

On the Popasului Street (Voluntari) – Bucharest Ring Road segment (4 km) work started in April 2012, whereas on the Petricani Street (Bucharest) – Popasului Street (Voluntari) segment (2.5 km) work was constantly delayed, partly because of remaining unfinished expropriations, until the contract was finally terminated in February 2015.

In December 2015, the construction work of the first 3.3 km of the motorway, the Bucharest Ring Road junction and the still under construction Moara Vlăsiei exit, was awarded to the joint-venture between Aktor and EuroConstruct Trading '98, for a cost of 129.2 million lei. They were planned to be completed by 2018, but the progress remained slow as of June that year. The entire segment from the Petricani Street to the Bucharest Ring Road was opened on 14 December 2018. The media has highlighted the facts that the motorway ends with a stoplight and it has a roundabout on its route, something unique in Romania, and widely regarded this segment as an "urban motorway".

Ploiești – Comarnic section The Ploiești – Comarnic section has been in pre-feasibility phase and its profitability is being considered. It is complemented by a relatively settlement-free section of the parallel national road DN1.

Comarnic – Brașov section Comarnic – Brașov section Section Length Period of construction Contractor Total cost Financier Status Section 1: Comarnic Sud – Comarnic Nord 5.2 km 68.6 m euro Re-tendered Section 2: Comarnic Nord – Bușteni 16.3 km Feasibility studies Section 3: Bușteni – Predeal 12.8 km Feasibility studies Section 4: Predeal – Râșnov 15.2 km Feasibility studies Section 5: Râșnov – Cristian 6.3 km October 2017 – December 2020 Alpenside 25.8 m euro State budget In service

Work on the Comarnic – Brașov section, the most difficult segment of the motorway, was due to begin in 2010 and take around four years to complete, but the French–Greek consortium Vinci–Aktor denounced the contract and construction was canceled. Total construction cost of this section was estimated at 1.2 billion euro.

The segment was re-tendered as a concession contract in February 2013. It has been awarded in December 2013 to the joint venture between Vinci, Strabag and Aktor, for a period of 29 years, with an estimated construction cost of 1.8 billion euro. This section of the motorway would have three twin tunnels, with a total length of 19.4 km, at Sinaia, Bușteni and Predeal, and four interchanges, at Comarnic, Bușteni, Predeal and Râșnov. The route would follow the river valley until Posada, where it would cross on the opposite side of the river and would run along the mountain range until Sinaia, from where it would then run nearly straight until Azuga, crossing through two twin tunnels that would bypass Sinaia and Bușteni, before crossing again to the eastern side of the river. According to media reports, work was expected to begin in April 2014, but was still pending, due to financial arrangements and the environmental certificate. According to the same reports, they had to be finalized in 2017.

As of June 2015, the concession had been canceled.

As of October 2015, section 1 (4.0 km) and section 5 (6.3 km, plus a connecting road) at the ends of the Comarnic – Brașov section were separately tendered. For section 1, a bid by Spedition UMB and Tehnostrade remained the only one, while the other tender was leaning towards a consortium led by the Spanish construction company Copisa. However, as of October 2017, after the termination of challenge procedures, only the Râșnov – Cristian segment was awarded for construction, to the Cypriot company Alpenside. The contract, which includes a 3.7 km connecting road, is worth 25.8 million euro and should take 6 months for planning and 18 months for execution. The bid for the Comarnic Sud – Comarnic Nord section had been canceled by February 2017, as the only bid was not in accordance with the terms.

In October 2018, the motorway Ploiești – Comarnic – Brașov (around 100 km) was once again tendered, as a public–private partnership, that would take 24 years and have an estimated cost of 1.36 billion euro. The Romanian state would contribute with 25%, while the private partner would contribute with 75%. As of December 2018, the tender's deadline, there were five companies or joint-venture interested. The project received criticism from the NGO called Asociația Pro Infrastructură for lacking details of major importance. In October 2019, it was announced that the joint venture selected for the construction work was China Communications Construction Company (China) – Makyol Insaat Sanayi Turizm (Turkey). The project was, once more, cancelled in the first quarter of 2020, by the newly elected government, in favor of a new future tender, based on European funds.

In August 2020, the segment between Comarnic South and Comarnic North (5.2 km, according to the project) was tendered again, for 68.6 million euro, with a contract length of 36 months, of which 12 months for the project and 24 months for the construction.

In December 2020, the Râșnov - Cristian segment was opened.

Brașov – Oradea section

This motorway segment, known as the Transylvania Motorway (), was split into three parts, with several subsections: the Brașov (Cristian) – Târgu Mureș (Ogra) segment (160.1 km), the Târgu Mureș (Ogra) – Cluj-Napoca West (Gilău) segment (89.7 km) and the Cluj-Napoca West (Gilău) – Oradea West (Borș) segment (165.5 km).

The segments in service of this section of the motorway are the Câmpia Turzii – Nădăşelu segment (61.2 km), under several openings between December 2009 and September 2018, the Ungheni – Chețani segment (31.6 km), under several openings between December 2018 and September 2020, and the Biharia − Borș segment (5.4 km). The Suplacu de Barcău – Borș segment (64.5 km) has been under construction since 2004, but the contract was terminated in May 2013, with the construction progress around 50%. Additional work is being performed on the Chețani – Câmpia Turzii segment (15.7 km).

Bechtel controversy The entire section was originally scheduled to be built by the American company Bechtel Corporation together with its regional partner Enka of Turkey. The contract was awarded in 2004 to the Bechtel Corporation by the Social Democrat Prime-Minister Adrian Năstase without an open bidding process, invoking "national security" as an excuse. The estimated construction cost was 2.8 billion € in 2003 and it rose to 4.7 billion € in a 2007 estimate. Although officially the deadline was set for 2013, the final cost and finalization date remained unknown.

As per the Romanian ministry of transportation, Anca Boagiu, the original contract was highly disadvantageous to the Romanian side. Following the contract renegotiation that occurred in June–July 2011, Bechtel agreed to lower the building cost per kilometer by 50% down to 6.9 million euro. Also it was decided that the American company will build only two segments (Suplacu de Barcău – Borș and Câmpia Turzii – Cluj-Napoca West/Gilău), leaving all the other segments of the motorway open for tendering.

Construction progress

Câmpia Turzii – Cluj-Napoca West – Nădășelu section