What is the purpose of dowel bar in elastomeric bearing?

Elastomeric bearing is normally classified into two types: fixed and free. For fixed types, the bridge deck is permitted only to rotate and the horizontal movements of the deck are restrained. On the other hand, for free types the deck can move horizontally and rotate. To achieve fixity, dowels are adopted to pass from bridge deck to abutment. Alternatively, in case there is limitation in space, holes are formed in the elastomeric bearings where anchor dowels are inserted through these holes. It is intended to prevent the “walking” of the bearing during its operation.

This question is taken from book named – A Self Learning Manual – Mastering Different Fields of Civil Engineering Works (VC-Q-A-Method) by Vincent T. H. CHU.