Answer
Wa `alaykum As-Salamu waRahmatullahi wa Barakatuh.
In the Name of Allah, Most Gracious, Most Merciful.
All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.
In this fatwa:
It is forbidden to exhume that grave unless the buried person has turned into dust.
Answering your question, the General Iftaa’ Department in Jordan, states the following:
The Shari`ah doesn’t permit exhuming or removing graves so long as they contain bones because the sanctity of their dwellers is similar to that of the living. Prophet Muhammad (peace be upon him) said about the sanctity of the dead: “Breaking a deceased body’s bones is exactly like breaking them when he is alive.” (Abu Dawud)
He also said: “It is much better for one of you to sit on a live coal, which will burn his clothes and get to his skin than to sit on a grave.” (Muslim)
These narrations highlight the sanctity of the dead and that preserving their graves against harm is obligatory because Allah the Almighty said: “We have honored the sons of Adam.” (Al-Isra’ 17:70) Therefore, not exhuming graves and not violating their sanctity is honoring their dwellers.
With regard to the above question, being adjacent to the main street isn’t a valid excuse for exhuming that grave since it was dug up with the blessing of the owner of that lot of land, and it is forbidden to widen that street at its expense; rather, its sanctity must be preserved.
In conclusion, it is forbidden to exhume that grave unless the buried person has turned into dust.
Almighty Allah knows best.
Source: www.aliftaa.jo