Where a highway authority seals a section of road that encourages higher speeds without providing adequate warning signage of dramatically changed conditions beyond the sealed section, this constitutes misfeasance (creating a trap) rather than mere non-feasance, and the highway authority immunity does not apply. The duty to warn arises when the road works are carried out, not only when accidents subsequently occur. Advisory speed signs are classified as incidental to road-making functions (subject to the non-feasance/misfeasance rule) rather than as traffic authority functions (to which the immunity does not apply).
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