Surprisingly good, this is what I was looking for—Col de la Bonette in France Alps in 2023

The Col de la Bonette is a 2715 m high mountain pass in the French Maritime Alps in the Provence-Alpes-Côte d’Azur region near the Italian border.

The pass forms the border between the departments of Alpes-de-Haute-Provence and Alpes-Maritimes. The narrow but continuous paved road (SG 3) connects the valley of the Ubaye at Jausiers (1240 m) with the valley of the Tinée at Saint-Étienne-de-Tinée (1144 m). At the turn of the millennium, the road was expanded to two lanes throughout, after some passages were still single-lane until the 1990s and two stream fords had to be passed. The Cime de la Bonette (2860 m) and the Cime des Trois Serrières (2753 m) are the peaks that make up the pass.

The summit of the Col de la Bonette is the starting point of a two-kilometre ring road that goes around the summit of the Cime de la Bonette and has a maximum altitude of 2802 metres above sea level. [1] The Col de la Bonette is the fourth highest paved Alpine pass with an altitude of 2715 meters and is only surpassed by the Col de l’Iseran (2770 m), the Stelvio Pass (2757 m) and the Col Agnel (2744 m).

The northern ascent to the Col de la Bonette is from the municipality of Jausiers via the C4. It is 22.2 kilometres long and has an average gradient of 6.7%, which corresponds to an elevation gain of 1493 metres. On the first half of the ascent, the gradient of the road is constant at around 7%, which winds upwards through the narrowing valley. After about eleven kilometres, there is a short flat section before the road begins to climb again. At an altitude of about 2600 m, the remains of the Casernes de Restefond are passed after about 20 kilometers. It is then another two kilometres to the Col de Restefond (2680 m). This forms the border with the Parc National du Mercantour, which the pass road crosses further on. From the Col de Restefond, the road continues to the Col de la Bonette, which is the actual culmination of this mountain route.

History
From 1890 onwards, several military buildings were erected in the area of Restefond and Bonette, two of which are located directly on today’s road. The north ramp leads around the fortified Casernes de Restefond, the ruins are still relatively well preserved. On the south-east ramp, the road passes through the Camp des Fourches at 2271 m[4], a former military camp whose houses are now only ruins.

In 1913, the Piste du haut was completed on the south-east side up to the Camp des Fourches. [5]

Between 1931 and 1940, bunkers were built on the Maginot Line,[6] visible e.g. above the road between the passes of Restefond and Bonette.

Between 1960 and 1961, the current street was built, as can be seen from the memorial stone at the highest point. In terms of transport, the connection is of little importance to this day.

Today’s route of the road was chosen over the top of the Col de la Bonette instead of the neighbouring Col de la Moutière (2454 m), which is a few hundred metres lower. The pass road over the Col de Restefond and the Col de la Bonette is 49.1 km long, the shorter connection via the Col de la Moutière, which has only been developed as a natural road to this day, is 45.7 km. This longer and higher course was probably chosen to obtain the prestigious title of “Highest Road in the Alps / Europe” and to be able to offer the traveller more impressive impressions. Another and more important reason that favored this choice in the period up to the Second World War was the military and strategic importance of the Bonette-Restefond ridge. The surveillance of this sector was essential for the control of the border area in the upper Tinée valley against the then hostile and fascist Italy.