Research into dispatch risk demonstrates the risk of collision from Start Against Signal SPAD (SAS-SPAD) due to train dispatch is minimal. This is because errors from both the driver and person dispatching the train must happen for a SAS-SPAD to occur. SAS-SPADs are a problem because the signal may not be fitted with Train Protection & Warning System (TPWS), and if the driver is not aware of the signal aspect, they may continue taking power after the SPAD.