When using a manual cross slope technique, what is adjusted to achieve a level reading?

The correct choice pertains to achieving a level reading by adjusting the down end of the level during the manual cross slope technique. This technique involves ensuring that the slope of the pavement is uniform and follows the specified cross slope requirements. By adjusting the down end of the level, the operator can accurately gauge whether the surface meets the desired slope grade.

This adjustment is crucial because it allows for precise measurement of the pavement's angle relative to a reference point, usually level with the other end of the leveling instrument. The goal is to maintain proper drainage and enhance the functionality of the roadway.

In this context, altering the length of the pavement or the angle of the road does not directly pertain to achieving a level reading with the manual technique; instead, these factors are typically determined by design specifications or project requirements. Similarly, the position of traffic cones is not related to the leveling process itself but rather may serve as a safety measure or guideline for traffic control, which is separate from the calibration of the cross slope.