In Bhutan, traffic drives on the left. The country has a fairly good internal road network with well over 3,000 km (1,800 miles) of surfaced road. The average speed is less than 40 kph (25 mph). The main routes run north from Phuentsholing to the western regions of Paro and Thimphu, and west-east, across the Pele La Pass and Thrumshing La Pass to the central valleys and eastern regions. The northern regions of the High Himalayas have no roads.
Due to the mountainous terrain, roads are frequently blocked by rock falls during the summer monsoon season. Therefore, it is best to avoid traveling long distances from the beginning of June to the end of August. However, if you must travel at this time, carry ample bottled water and snacks because if the landslide is substantial it could take some time to clear the road.
An international driving permit is required to drive in Bhutan.