The city of Urbandale failed to take into account the unique nature of properties along 156th Street when it calculated assessments to pay for a street paving and sidewalk construction project, the Iowa Court of Appeals ruled today.

Six property owners challenged the assessments, which ranged from about $15,000 to slightly more than $104,248 for their properties. A Dallas County District Court judge had ruled that the city overestimated the public benefit to each property, and ordered that the assessments be reduced 75 percent for the street project and 50 percent for the sidewalk project.

The appeals court upheld that ruling, but found that the Dallas County judge did not have the authority to grant landowners a 10 percent reduction on their assessments if they were paid in a lump sum within 90 days.