The Georgian S5 route (Georgian: საერთაშორისო მნიშვნელობის გზა ს55, Saertashoriso mnishvnelobis gza S5, road of international importance), also known as Tbilisi-Bakurtsikhe-Lagodekhi (Azerbaijan border) or Kakheti Highway, is a "road of international importance" within the Georgian road network and runs from Tbilisi via Sagarejo and Bakurtsikhe to the border with Azerbaijan near Lagodekhi over a distance of . After crossing the Georgian-Azerbaijan border the highway continues as M5 to Zagatala and Yevlakh. The S5 highway is one of the two Georgian S-highways that is not part of the European or Asian international highway routes. Within the Georgian S-network it connects with the S9 Tbilisi Bypass.
Referring to its main location, the Kakheti region, the road is nicknamed "Kakheti Highway". While the segment in the capital region until the Tbilisi Bypass intersection has been built as a 6 lane city express road, and has been so until the airport since the 1970s, the rest of the highway is a 2 lane highway which passes through towns and villages. To improve traffic flow in the crowded Alazani valley, a bypass is planned between Bakurtsikhe and Tsnori, and the Tbilisi Bypass - Sagarejo section is scheduled to be upgraded to a 2x2 motorway.
Background
Since the early 1980s the current S5 route was referred to within the Soviet road network as A302 between Tbilisi and the junction West of Lagodekhi. Beyond this point the road was part of the A315 to Zagatala and further into the Azerbaijan SSR. Prior to the 1980s the route of today's S5 was unnumbered as was the case with most Soviet roads.
After Georgia regained independence in 1991, the Soviet route designations were maintained until 1996 when the current route numbering system was adopted. In that year the "roads of international importance" (S-)category was introduced and the "S5 Tbilisi-Bakurtsikhe-Lagodekhi (Azerbaijan border)" replaced the old A302 and A315 designations.
Future
In 2021 contractors were signed for a new motorway section of the S5 highway, between the Tbilisi Bypass (S9) and Sagarejo. The project is divided in three lots and will be financed by the state. Chinese and Turkish companies will build two lots of in total, while a Georgian company will be responsible for the remainder. The redesigned section will bypass villages and towns. Due is an upgrade of the Sagarejo-Badiauri section of , for which the World Bank committed to financing.
Also a km bypass between Bakurtsikhe and Tsnori has been announced. The tender for this section has been completed in 2021. This section of the S5 in the Alazani Valley is densely built up and has a chain of villages and towns. Similarly, the Gurjaani Bypass was opened north of Bakurtikhe in 2021.
Route
The reference point for the mileage of roads leaving Tbilisi, such as the S5 highway, is Freedom Square according to the Georgian "Law on motor roads". But that does not mean Freedom Square is the actual starting point of the highway. In the case of the S5 the actual starting point is George W. Bush Street east of the city centre and about from Freedom Square. The main speed limit is with the exception of passage through towns and villages (, may vary locally) and within the Tbilisi city. With the exception of the Tbilisi part, the highway is a two lane road throughout and doesn't have major differences in altitude: it hovers around above sea level, reaches its lowest point of asl in the Alazani Valley and its highest point of asl near Sagarejo.
Tbilisi - Sagarejo
The Kakheti Highway starts in George W Bush Street the "Kakheti Highway" as a 2x3 lane city express road, with parallel lanes until the airport exit just before the Tbilisi Lilo area. In 2020 the stretch until the Tbilisi Airport has been completely rehabilitated. Through Lilo the road is a 2x2 lane city road after which the road reduces to a two lane highway until its terminus. From this point a 35 km 2x2 motorway to Sagarejo has been planned, with construction works being anticipated. Heading East the S5 highway runs through the dry East Georgian lands passing a few villages and some hills along the way. Just East of Vaziani the Sh38 state route offers an alternative to north Kakheti and Alazani valley via the Gombori Pass. Near Sagarejo the highway skirts along the foot of the Gombori mountain range which extends in southeasterly direction from the Caucasus range and separates the Iori and Alazani river valleys. Sagarejo is the regional centre of this part of Kakheti, and it offers the northern access road to the historic David Gareja monastery complex on the border with Azerbaijan.