(Note: this is not a treatise on traffic law, but a general guideline, covered by the general spirit of traffic regulations like hinted at in Section 23103(a) quoted below. It should help the OP to sort his thoughts, not be used as base for a court case. It is meant to help the OP answer the question of whether a traffic rule can *make him kill a human*, not for minor cases like flinging pebbles...)
Road traffic laws are a bit like air traffic laws in this respect: they hold true until lives or property are in severe danger. Then they turn from law into mere suggestion.
No single rule or combination of traffic rules can force you to do anything at all that damages other persons or property. If breaking a traffic rule is the only way to avoid damaging something or someone here and now, then you must break that rule. Taking lives or damaging property is against laws as well, and the other laws are more important since they have intrinsic value - there is no additional value to traffic laws except they help to regulate traffic (which means that they avoid danger and damage).
Section 23103(a) (as posted by @Dawn in her answer, thank you):
A person who drives a vehicle upon a highway in willful or wanton disregard for the safety of persons or property is guilty of reckless driving.
The guy in the yellow suit is just an extension of the traffic rules. He can tell you whatever he likes (just like an aircraft controller can tell the pilot whatever he likes), but you, the driver, have full responsibility over whatever happens. You must disobey the command of the yellow suit if it would lead to damage.