interpretation of a statute

I recieved a ticket for "following too closely" (Indiana statute 9.21.8.14). The statute reads:

IC 9-21-8-14
Sec. 14. A person who drives a motor vehicle may not follow another vehicle more closely than is reasonable and prudent, having due regard for the speed of both vehicles, the time interval between vehicles, and the condition of the highway. As added by P.L.2-1991, SEC.9.

I was travelling in the far left lane of a three lane interstate. In front of me, in the middle lane, was a semi followed by a pickup truck. The pickup truck changed lanes in front of me. I applied my brakes (If i hadn't I would have rear ended the pickup). I placed my right turn
signal on to change lanes. As i entered the center lane the police officer came up behind me with his lights on. In our exchange on the shoulder of the road, the officer stated that it was my brake lights coming on that drew his attention to me. I asked him if he had seen the pickup change lanes in front of me. He avoided the question and said I was free to go. He was NOT in any way rude....he simply did not answer.

The statute makes no reference to a time frame. Imagine you are driving down the interstate and someone changes lanes in front of you. Are you instantly guilty of this traffic violation? I'm sure that there is some common sense interpretation of this statute. Does anyone have any case law or experience in a similiar circumstance? Does anyone know how this type of statute is generally interpreted?

Thanks.

If you ,by your own admission ,had to apply your brakes to avoid crashing into the pickup in front of you on an interstate, you are guilty of following too closely.
Keep in mind there are situation that are unforeseeable like a wreck in front of you, but, you are required to leave enough distance in front of you to give you ample time to react defensively to other drivers safely.