Global Roads Open Access Data Set
Compiled by CIESIN at Columbia University. Downloadable here. Used by Dreher et al. (2015). Part of the data comes from Vmap0 Road Data (described below).
Vmap0 Road Data
A geo-referenced data of the road network around the world, created by US government. Can be obtained at FAO GeoNetwork (you need to obtain the log-in ID and a password from FAO). See this post on Vmap0 data.
By Googling "Vmap0 Road", you'll see a couple of webpages (like this one) claiming that the accuracy of this dataset is questionable. See this article for more.
CIAT Latin America and the Caribbean Roads Database
Used by Acemoglu and Dell (2009), although I cannot locate it on The International Center for Tropical Agriculture (CIAT)'s website.
Africa Infrastructure Country Diagnostic
The initiative led by the World Bank has produced road map data for quite a few countries in Africa, downloadable here. Used by Bllimpo, Harding, and Wantchekon (2013) and by Storeygard (2016).
UN OCHA Geodata
Niger, Brundhi, Liberia, etc.
FEWS-NET Africa Data Dissemination Service
For Burkina Faso, Chad, Mali, Mauritania, and Niger,
a webpage in FEWS-NET's Africa Data Dissemination Service provides road network data. Scroll down to the bottom.
For Burundi, DR Congo, Egypt, Eritrea, Kenya, Rwanda, Sudan, and Tanzania, the AfriCover project provides road network data created from satellite images. To download, register first. Then click the metadata and submit reasons and expected outputs to request the authorization for downloading the data.
See this post.