Yes it may do, actually I suspect it probably does (from what Harley says I suspect the OEM navigation unit may uses it - but I don't have the pin-out for one of those), see last paragraph.
While neither pin-out for the
GD & GD-01 Headunit Pinout or
GD-02 Pinout head-units (the two which are OEM fitted in AU - i.e. by HMCA) label a 'speed' connection. They are, however, only the
head-unit pin-out and simply show 'N/C' (Not Connected), for some pins, meaning the head-unit doesn't use it.
It doesn't mean the signal isn't present on one of the wires, for an N/C pin, in the connector that plugs into it, but it doesn't guarantee it. But Hyundai seems pretty consistent on keeping things consistent on things like which pin does what in connectors to things like head units, cameras, etc. where the same connector/plug is used.
Therefore it is probable (but no guarantee) the wire for the 'Speed' pin (B16) on the 'Generic' unit pin-out, shown on
GD & GD-01 Headunit Pinout will have the speed signal in your i30. Of course this is only a guess - so could be wrong. If you do connect it please lets us know how it went.