I'm planning on taking a stab at India, focusing on the state of West Bengal (as I've been there).
India has four systems of note: AH, of which is already drafted
NE, their National Expressway system, and not relevant to West Bengal
NH, their National Highway system
SH, each state's respective highway system
Based on field observation, 'headache' is a compliment. In 2010, the Ministry of Roads and Transport completely renumbered the NH system, converting it to a grid-like system like the US highways. In this instance, odd numbers run west to east, with 1 in the north and 87 in the south, and even numbers run north to south, with 2 in the east and 68 in the west. However, as of February 2020, none of the NH in West Bengal have been renumbered in the field.
Additionally, OpenStreetMap does not have accurate mapping outside of Kolkata, and there is no GMSV coverage in India. In several instances, Google Maps has the best mapping (even when comparing against OSM, Bing, MapQuest, and RMN), though Google itself has some errors I've noticed.
Wikipedia has a very detailed city itenary list for the NH here:
https://en.wikipedia.org/wiki/List_of_National_Highways_in_India_by_highway_numberFor official sources for our bibliography, the pdfs in the links should suffice and I will verify when I get a chance.
As for State Highways, I've yet to begin formal research and am relying on field observations for West Bengal. I'll be using West Bengal as a test state, as that will give me an idea how comprehensive the entirety of India will be.