= Solution
A <doubly linked list> supports backward traversal and removal of a known <linked list node> in <constant time>, because that node supplies its own predecessor. In a <singly linked list>, removing a known node generally requires finding its predecessor by a forward scan unless the caller already supplies it. Inserting before a known node has the same advantage.
The cost is another pointer per node, more link assignments on every update, and a stronger consistency invariant to maintain. Hence
$$
\boxed{\text{bidirectional access and constant-time local deletion, with extra storage and updates}.}
$$
This does not make locating an arbitrary data value faster: a search still takes <linear time> in the worst case.
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