A plaintiff claiming damages against a public authority for inadequate road maintenance must prove on a balance of probabilities that the alleged inadequate maintenance caused or contributed to the accident. The onus cannot be reversed to require the authority to prove adequate maintenance. Where a driver operates a vehicle at excessive speed in wet conditions on a gravel road, knowing such roads become slippery when wet, and no other vehicles experienced similar problems on the same stretch of road in similar or worse conditions, the excessive speed is the sole cause of any resulting accident. The condition of a gravel road that is typical of such roads generally, even if less than ideal, does not establish negligence in maintenance absent proof that it caused the accident.