Non-intrusive detection devices are typically installed over or ___________ to the roadway?

The correct choice highlights a key aspect of where non-intrusive detection devices are positioned relative to the roadway. Non-intrusive detection devices are designed to monitor traffic without requiring physical modifications or disruptions to the road surface. Therefore, the term that best captures this placement is "next," as it emphasizes proximity without direct contact.

Installing devices next to the roadway allows for effective monitoring of traffic flow while minimizing the impact on the road infrastructure. This approach facilitates easier installation and maintenance while preserving road usability for vehicles.

In contrast, other terms like "adjacent" or "above" might suggest alternate positioning, but "next" effectively captures the intended relationship of being close to the roadway without implying direct interaction or support from it. Hence, "next" accurately describes the typical installation method for non-intrusive detection devices.