Being rarely used is an advantage, though. You can solve the safety hazard component of the problem with a few hundred dollars worth of signs and barriers, rather than by actually repairing the thing. The convenience part can then be ignored.
If you do this in a college town or something, have fun replacing those signs and barriers every few weeks, as they are graffitied, vandalized and stolen.
My parents live in a community where one of the roads is named something like "High Street" (not actually that; it's a little road within their development). That sign gets stolen a few times a year by college students from the next town over because it includes the word "high". They have never had a road barrier stolen or meaningfully damaged, though -- they have maybe a dozen in various places.
They budget about $50/year to replace the signs. Still much less, even over rather a long period, than the cost of rebuilding a bridge.
Ideally, the concrete jersey barriers are temporary until the bridge is either repaired or dismantled appropriately (with proper road closure on both sides).
It still blows my mind that a bridge on an otherwise publicly accessible road was privately owned and maintained. That's a new one to me - around here, there are plenty of private neighborhood roads, but none have bridges.
