For starters, there is the principle of sovereign immunity. This holds the government can’t be held liable for negligence unless it specifically grants permission for such action. Most states have a predetermined list of conditions one must meet in order to have a valid case. For example, action can be brought against a government for negligence of a government employee only if that employee was carrying out a ministerial function, as opposed to a discretionary one.
Beyond that, there are often strict notification requirements and short windows in which to inform the entity of the intent to sue and to take certain action to do so. This is true even when the same general statute of limitations is applicable.