Statute of Limitations on Bond Use?

Georgetown has general obligation bonds that were issued in 2008 that have not been used.

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Over 50% of the authorized general obligation bonds have NOT been issued or used!

Is there a time limit for the use of these bonds? Why hasn't the money been spent on the roads and parks that the City promised the voters when the 2008 bonds were authorized?

Is there a plan to use these authorized bonds on projects?

Inquiring minds would like answers.