With the highest point at 1,085 metres (3,560 ft) above sea level, the road is sensitive to snow conditions and foul weather during the winter season, during which the mountainous sections, especially near Haukelifjell skiing center, may be closed in short periods. The stretch of road through the mountains is called Haukelifjell.
A road over the mountain along this route was opened first time in 1889. In 1968, the Haukeli Tunnel (5.6 km (3.5 mi)) was opened allowing reliable wintertime traffic.
The road was numbered as European route E76 before 1992, when the numbering system of all of the European routes in the Nordic countries was revised. Initially, there was not room for it in the system, and road became called Norwegian National Road 11 (Riksvei 11). Due to local wishes and steadily increasing of the road standard during the 1990s, it again received European route status, with the number E134.
The route has many tunnels, especially in the mountainous sections in the central and western parts, especially along the Åkrafjorden, where is passes the Langfossen waterfall. Prior to the opening of the tunnels, some of the fjord sections of the road were quite steep and very narrow; around 5 metres (16 ft) wide. This was far less than the 8.5-metre (28 ft) minimum requirement for European routes, and well below the minimum requirement to allow two trucks to pass. During the 2010s, a new series of upgrades has been planned to further improve the road in the Seljord-Hjartdal area as well as in Vindafjord.
In 2011 E134 was extended by 10 kilometres (6.2 mi), to end at Haugesund Airport instead of near city centre. In 2018 E134 was extended by 40 kilometres (25 mi), to include the Oslofjord Tunnel, letting it end at Vassum at the European route E6 in Frogn municipality in Eastern Norway. In 2019 the E134 was shortened by about 10 km by being routed through the newly opened Mælefjell Tunnel.