Is bicycles safe to ride at night?

Mine seems to be unbalanced - but generally at night - when its dark. Could it be fluid in the tyres that comes out at night perhaps? Does any you else have this problem? The nights I cycle back from the bar (anytime from 10 pm), the bicycle swerves and unbalances. I have knocked into several parked cars like this,... show more Mine seems to be unbalanced - but generally at night - when its dark. Could it be fluid in the tyres that comes out at night perhaps? Does any you else have this problem? The nights I cycle back from the bar (anytime from 10 pm), the bicycle swerves and unbalances. I have knocked into several parked cars like this, as it wont drive straight. During the day it seems fine. Or me get a new bike??
Update: Some cyclists here have no sense of humour or knowledge of irony!
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