Tax swerving

 A man was driving away from the tax office when all of a sudden he has to swerve to avoid a box falling off the lorry in front.

Seconds later a policeman pulled him over for reckless driving. As the policeman starting writing the ticket he noticed the box was full of nails and tacks.

"I had to swerve or I'd have run over those and blown my tyres!" protested the driver.

"Ok", replied the officer, ripping up the ticket, "but I'm still bringing you in."

"What for?!" retorted the man.

"Tacks evasion", answered the policeman.