Do better roads promote migration or do they discourage it?

Empirical evidence on the impact of improving road networks and transportation systems on migration in developing countries remains scarce and generally provides mixed results. This paper fills part of this empirical gap in the Tanzanian context by answering the following question: do better roads promote migration or do they discourage it? A difference-in-difference estimation is implemented using the Kagera Health and Development Surveys (KHDS), coupled with information on trunk roads upgraded to bitumen standards in the region. On average, migration decreases as upgraded roads improve local living conditions. The impact proves to be greater in absolute value for well-connected communities, as well as for the probability of moving within the Kagera region. However, the effect decreases over time.

That is from a paper (Journal of African Economies, July 2013) by Marie Castaing Gachassin. I did not find the full paper online. By the same author, but from a different paper, I took a table of road density in African countries (other tables and graphs in the paper are also interesting). 

Does paving roads have a political return?

This paper found that it does:

[I]ncumbent vote share would be, on average, 7 percentage points higher in a section that went from zero streets paved to fully paved by the politician. The politicians’ vote share would increase from 0.34 to 0.41 as a result of this policy.

This study was conducted in Acayucan, a metropolitan area in Veracruz, Mexico. 
These two pics from the paper are illustrative of the change:

Source.

As a side: the road infrastructure in the surrounding towns of Guatemala City is deteriorating rapidly. The effect however is not the same all over. There are some municipalities that are much more efficient than others at maintaining the roads quality. There is one case that shines particularly. It is the municipality called Santa Catarina Pinula. [Some pics here]. In SCP the roads are perfect, and the schools are new and clean. From what I can see on the streets this is a case of a successful local government. The major won the elections again! [May be he read the paper!].