When you come to Martinique with your family, the best is to rent a minivan so that the entire family and you luggages fit in.
We have minivans with 5, 7 or even 9 seats ! Make your choice :)
Renting a minivan can also be useful if you have surfing boards to carry around the island with you. Anyway, to rent a minivan you need :
To be 25 years old minimum
To have your driving licence for more than 2 years
To bring at the agency : your driving licence, an ID, a credit card (for the deposit).