R3 is a mostly planned expressway (Slovak: rýchlostná cesta) passing through central Slovakia in the north–south direction along the European route E77.

It goes from border with Hungary, moving north around Krupina to Zvolen, from there is currently planned to share an 18 km section with R1 and R2 from Budča to Žiar nad Hronom. There is also planned shared section between Žiar nad Hronom and Ráztočno near Handlová with R2. Then continues north, from Martin sharing a section with the D1, then splitting off in either Hubová, going from Dolný Kubín through the Orava River valley to Trstená and ending at border with Poland.The motorway goes along the route I/59,I/18,I/65 and through I/66

From the total length of cca. 230 km (excluding shared sections), these sections are in operation:

• 7.2 km Trstená bypass (two-lane)
• 5.7 km Oravský Podzámok - Horná Lehota (two-lane)
• 1.7 km Martin - Martin, North
• 4.3 km Horná Štubňa bypass (two-lane)

What's in construction of the R3 is:

• Tvrdošín-Nižná to be completed 2023

The route of the R3 which is designed in three parts, in the north from Trstená to the intersection with the D1 highway in Likavka, in the central part from the intersection with the D1 highway in Martin to the intersection with the expressway along the R2 road in Ráztoč and in the southern part from the intersection with the R1 expressway in Budča to the state border of Slovakia with Hungary near Šahy, where the R3 will connect to the Hungarian highway M2. Even though the connection of the R3 road to the Polish highway network is currently not expected in the north, due to the currently missing highway construction project on the Polish side, this position will probably change in the future. In 2019, the preparation of a technical study was launched in Poland for the continuation of the Polish expressway S7, from the current termination in Rabka-Zdrój to the state border with a prospective connection to the R3 road. The technical study of this road was completed at the end of 2020, Poland envisages the construction of a high-capacity four-lane road. Between Šahy and Dudince, the R3 road will intersect with the R7 road.[2][3]

The total length of the R3, with the exception of toll roads, i.e. sections that the R3 route shares with other highways and expressways, is approximately 200 km. In the case of the route of the southern part of this road, in the section roughly between Zvolen and the state border with Hungary, the technical study also allows the possibility of ending the road R3 in Štúrovo instead of Šahy and at the same time, the technical study also allows the possibility of the route of the road R3 through Hronský Beňadik instead of Budča. The specific route of the R3 road in the southern section has not yet been determined. The southern section of the R3 expressway is at the same time the oldest in terms of plans, as the highway in this corridor is already mentioned in the Resolution of the Government of the Czechoslovak Republic No. 286/1963 from 1963. This resolution envisaged the construction of highway No. 66 in the section from Zvolen directly south to Šahy.

The lengths and routes of individual sections listed below are based on provisional construction plans in 2020, but considering the fact that many sections of the R3 road are only at the beginning, it is almost certain that the lengths and routes of unbuilt sections will still change. In 2020, there was a total change in the routing in the area of Dolný Kubín and in the section from the D1 highway to Dolný Kubín. Road R3 is to be implemented to a considerable extent as a reconstruction or completion of the existing road I/59. The R3 road through the town of Dolný Kubín has been newly extended. The planned intersection of the R3 road with the D1 highway was moved from the Hubová location to the Likavka location.

The international route E77 passes along the route of road R3. R3 will lighten traffic on the Kremnické Bane mountain pass, which is located on I/65. Construction on almost the entire length of R3 will require the relocation of roads, watercourses and engineering networks, as part of environmental protection, sewerage with the separation of oil substances and noise barriers will be built. The construction of two tunnels is tentatively planned for the R3 route; Biela Skala (630m) and Sklené (3450m). Both tunnels are located on the planned Horná Štubňa - Ráztočno section. According to the current plans of the Ministry of Transport, with the exception of the section near Tvrdošín, no sections of the R3 road will be constructed or open until 2028. Sections at a high level of preparation were not included in the plans either. With regard to the current intentions of the Ministry of Transport, the operation of the expressway along the entire length of the route cannot be expected before the year 2050.[4][5][6]