What is the maximum allowable error of closure for urban differential leveling surveys?

In the context of urban differential leveling surveys, the maximum allowable error of closure is determined by the precision and accuracy standards expected in urban environments, where infrastructure and existing landmarks can impact measurements. An allowable error of 0.04 (or 4 hundredths of a foot) reflects the typical expectations for high precision needed in urban settings. This level of accuracy is essential to ensure that leveling surveys can properly control for factors like elevation changes, construction effects, and other civil engineering considerations common in densely populated areas.

This standard is consistent with regulatory guidelines that govern surveying practices, ensuring that surveys maintain a level of reliability necessary for legal, engineering, and construction purposes. Adhering to these limits helps minimize potential errors that could lead to significant issues in infrastructure design and implementation.

In contrast, the other options propose either a lower or higher allowable error, which would not meet the typical standards required for urban differential leveling. A lower error value would imply an unrealistic level of precision for many practical surveying applications, while a higher value could lead to unacceptable discrepancies in measurements that could affect the overall integrity of construction and development projects.