Final answer:
Limited compatibility with emerging technologies is not a benefit of future-proofing an ETTS installation; it is a disadvantage as future-proofing should ensure ongoing compatibility with new technologies.
Step-by-step explanation:
The question posed addresses the topic of future-proofing an Electronic Toll Collection System (ETTS) installation and its benefits. When we talk about the concept of future-proofing, it generally involves preparing a system to handle future events or developments to minimize negative impacts and ensure smooth operations. In this context, the benefits typically include increased system reliability, scalability for future technology upgrades, and reduced maintenance costs. However, Option 4, which refers to limited compatibility with emerging technologies, is NOT a benefit of future-proofing. It is a disadvantage, as future-proofing aims to ensure compatibility with future technological advancements. Therefore, limited compatibility with emerging technologies would be a failure to future-proof effectively.