Proceedings with respect to public improvements to be paid for in whole or in part by special assessments shall be liberally construed by the legislative authorities of municipal corporations and by the courts in order to secure a speedy completion of the work at reasonable cost, and the speedy collection of the assessment after the time has elapsed for its payment. Merely formal objections shall be disregarded, but the proceedings shall be strictly construed in favor of the owner of the property assessed or injured as to the limitations on assessment of private property and compensation for damages sustained.

With respect to any assessment upon the abutting, adjacent, and contiguous, or other especially benefited lots or lands in a municipal corporation for any part of the cost connected with an improvement authorized by law, the passage by the legislative authority of an ordinance levying such assessment shall be construed a declaration by such legislative authority that the improvement for which it is levied is conducive to the public health, convenience, and welfare. No assessment shall be held invalid by any court because of the omission of the legislative authority to expressly declare in the proceedings and legislation for such improvement and assessment that the improvement is conducive to the public health, convenience, or welfare.