This is why I don't like this kind of metaphor, and I don't like the Technical Debt metaphor. Because it doesn't convey the right concept. It conceals, obfuscates actual truths.
- Bad code - Bad decisions - Bad design - Lack of maintenance - Lack of proper business concept understanding
Those things mean something, you can make them more precise, but they could be actionable. Technical debt always needs a follow up question: so what is actually going on?
The city now wants to add bike lanes to Market Street and is anticipating the same issues.
The issue at hand is self-explanatory.
Poorly maintained roads and bridges ARE obviously a drag on future work, since nearly all other work depends on them for transportation, it drives up costs (eg. potholes start to drive up maintenance costs for vehicles and increase commute times), and reduces tax revenues (whether it is through depressing real estate prices or other mechanisms).
The key piece I would add is to point out that it is much cheaper to maintain the bridge rather than replace it if it fails.