Surface evenness affects vehicle speed, comfort, vehicle operating cost and safety and hence needs to be require do this test after construct road/road pavement
Benkelman beam test is useful to determine pavement material properties (such as elastic modulus), to determine a pavements structural capacity, to locate inadequate subgrade support condition (e.g. voids) and to evaluate joint condition.
The modulus of elasticity E is a material property, that describes its stiffness and is therefore one of the most important properties of solid materials and test result useful in structural analysis and design.
Field CBR tests are used for evaluation and design of flexible pavement components such as base and subbase course and subgrades and for other applications (such as unsurfaced roads) for which CBR is the desired strength parameter.