Martelly, who leaves the post after five years in office, delivered a farewell address to Haiti's National Assembly on Sunday.
Two presidential runoffs in October and December were postponed
amid security concerns and "because such large swatches of Haitian society had rejected the election," explains Jake Johnston, research associate for the Center for Economic and Policy Research, who is currently in Port-au-Prince.
Protests and flashes of violence have added to the precariousness of the situation on the ground.
An agreement for a transitional government was reached just 22 hours before Martelly left his post.
Under the terms of the new agreement, Haiti's parliament will elect an interim president for a term of 120 days and confirm a consensus prime minister.
A new round of elections will take place on April 24, with the elected winner to be installed on May 14.
U.N. Secretary-General Ban Ki-moon called for "calm and stability" in the Caribbean nation Monday, adding that the U.N. reaffirms its commitment to "offer full support to the Haitian people in the fulfillment of their democratic aspirations."
But Johnston also says there are other concerns on the ground and much yet to be decided, "including if there will be a further investigation into fraud in the October vote."
"The key for whoever is provisional president is to restore credibility to an electoral system which no longer has the trust of the Haitian people. Less than a quarter of all registered voters participated in October. In order to achieve this, first, there must be an investigation and verification of the October 25 vote," Johnston said.