In a simple answer, yes you can but under certain criteria. If the condition of the existing pavement is in poor state (major cracks, settling etc.) it may be a better solution to start over and build the base system up properly. Also, do you have enough threshold clearance to accept a 2 3/8 thick paver plus the 1” sand bedding course? Another consideration is how you will adjoin the pavers to meet other existing pavements (garage surfaces, sidewalks, etc.). If you find your existing pavement meets these conditions, then pavers can be installed on your pavement with a few modifications to the installation process.