Please answer a question about the following article about Kathmandu:

The total length of roads in Nepal is recorded to be (17,182 km (10,676 mi)), as of 2003–04. This fairly large network has helped the economic development of the country, particularly in the fields of agriculture, horticulture, vegetable farming, industry and also tourism. In view of the hilly terrain, transportation takes place in Kathmandu are mainly by road and air. Kathmandu is connected by the Tribhuvan Highway to the south, Prithvi Highway to the west and Araniko Highway to the north. The BP Highway, connecting Kathmandu to the eastern part of Nepal is under construction.

In what direction out of Kathmandu does the Prithvi Highway travel?
west