Travelling at speed suggests trying to achieve a fast result.
Speeding – as in a traffic offence – suggests being too focused on an end result, and not the method of getting there. However, as the opposite to fast, being slow in dreams gives a sense of greater tranquillity than such frenetic behaviour.
To be taking, or to be given, speed (amphetamines) in a dream may have two meanings.
If the substance is used in everyday life, we could be being alerted to a gift or talent that should be developed.
If we do not normally use the drug, then we are putting ourselves in danger in some way. We may be trying to force an issue or pre-empt results.