It was a classless, inadvisable thing to do under any circumstances, but when the prankster reached out the truck window and touched Jason Bulton on the back, he had no idea what he was starting.

You know that old song about "you don't pull on Superman's cape, you don't spit into the wind, you don't pull the mask off the ol' Lone Ranger ... ?"

You also don't mess with J.B. when he's riding his bike.

There were no injuries that resulted, no pileups and not even — and this was due entirely to the fact that try as he might, Jason couldn't catch up to the truck — any physical altercations.

But what the two men in that truck, out to have a little immature fun at the expense of an unsuspecting cyclist, did not know was that they had slapped on the back the most passionate, most ardent, most aggressive advocate of bicycle safety in the state of Utah, if not the entire Intermountain West.

Oh, and also — Bultman is 6 feet 4 inches tall and weighs 220 — the biggest.

Although he couldn't catch it, Bultman could memorize the license number of that truck, information he turned over to the police.

The result is the first-ever test of Utah's three-foot law in a court of law.

When authorities locate the driver of the truck, they will arraign him on charges of being less than 36 inches away from Bultman and his bicycle.

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The so-called three-foot law was passed by the Legislature in 2005 after the deadly summer of 2004 that saw three Salt Lake-area bicyclists die in bike-car collisions.

The law stipulates, as its title implies, that motor vehicles must allow at least three feet between them and bicycles.

Bultman, 35, an engineer who commutes to work daily, year-round on one of five bikes he owns, could have chosen to charge the truck passenger who reached out and touched him with assault, or he could have charged the driver with reckless driving.

But he opted for the three-foot law for two reasons.

One, "I want to show that the law is enforceable." And two, "I want to educate the general public that by and large doesn't know the law exists."

And if the court needs an expert witness to testify about bike laws, Bultman could call himself.

Few people anywhere are more versed on the subject. The Florida native is a former chairman of the Mayor's Bicycle Advisory Committee and current president of the Salt Lake City Bicycle Collective, a group he helped organize in 2002. In 2007 he was named Bicycle Advocate of the Year.

"My side job is bicycle advocacy," says Bultman, who does not personally own a car.