Yes, the current Castle Creek Bridge is safe. As we get closer to the end of its useful life, repairs will be more frequent.
A good analogy for how bridges age is that they are like a paperclip: you can bend it and twist it and then it hits a point when it breaks.
When the Castle Creek Bridge starts to deteriorate, the first step will be to limit the weight of vehicles that go across the bridge – so heavy construction vehicles, large delivery trucks, big fire trucks, and buses will be the first to be prohibited from crossing the Castle Creek Bridge when and if the condition of the bridge warrants weight restrictions.