If the policeman cracks a smile at any point, immediately let go, smile and say "who pays your paycheck?". The multiplier for a smiling policeman is x500 because there's not a snowball in hell that he'll smile to begin with, so (10sec x 500 = 5000). Operation driver's license chicken is not about agitating policemen, but about reminding them the customer is always right.
The next day is round 2. If it's the same policeman, you're not multiplying anything by anything because you'll be on to the next challenge, hand cuff chicken.
Extra credit: Have your passenger record video for posterity. Add 5,000 points to total your score, because you just leveled up to straight jacket chicken.
See also: toll booth chicken, drive-thru chicken