MONTREAL, Que. –His patrol car parked squarely in an Autoroute 20 merge lane on the edge of Montreal, carrier enforcement officer Arnold Yetman unpacked the smoke meter. He barely had the sooty instrument turned on and calibrated when his partner, another carrier enforcement officer parked at the top of the steep off-ramp on the far side of the overpass, radioed him.

Yetman muttered in his mic’. To me: “We have one, but the driver turned instead of following the agent’s (that’s what Yetman called the other officer: the ‘agent’) instructions to drive straight. We know why, and it is going to cost him a lot of money. But we won’t tell him till after we do the opacity test.”

I was out for a first-hand look at how Control Routier Quebec tests trucks for compliance to emission standards that came into force in 2006. Warned a year ahead of time of the new standards under the programme d’inspection et d’entretien des vehicules automobiles lourds (PIEVAL), aka heavy-duty vehicle inspection and maintenance program, many carriers tuned up their trucks. The government measured an improvement in Montreal’s air quality and gave the trucking industry all the credit.

“Will you tell me?” I asked Yetman, referring to the elusive driver. “He’s driving with a suspended licence.” Poor schmuck, I thought.

A few minutes later a 1988 International flatbed, escorted by the agent in his patrol car, rumbled up and stopped in front of the gear Yetman had laid out on the sidewalk. The agent pulled two fat rubber wheel chocks out of his trunk and kicked them into place fore and aft of one of the flatbed’s doubles. Yetman kneaded cleaner into his hands, then wiped off the jelly and soot with brown paper towel.

While the agent checked the driver’s papers, Yetman gave him the drill: “When I give you a thumb’s up, put the pedal to the floor and keep it there till I do thumb’s down. We’re going to do this six times.” Earlier, Yetman had told me, “Some drivers don’t like that. They think it will wreck their engines, but it won’t.”

It took a few minutes to position the Model 1667 Smoke Check, manufactured by California-based Red Mountain Engineering, over the end of the exhaust pipe. (The French call it an opacimetre, since it measures exhaust opacity; ie., how much light the exhaust blocks). Control Routier Quebec’s Montreal office only recently acquired the machine and this is the first time the two officers have taken it out since being certified to use it.

I sampled the breeze, moved upwind, then ducked down for a picture. “Stand back,” Yetman advised. “Sometimes we disappear (in the smoke) when we do this.” I stepped back, crouched, twisted the barrel of my lens and waited.

One, two, three thumbs up and down blew the gunk out of the pipes. Clouds of smoke rolled away. Four, five and six were the money readings, which were then averaged to get a reading of how thick, how opaque the exhaust was. The agent squatted by a small suitcase containing the brain of the smoke meter and a printer chattered out a report. The opacity was 47.7%, below the 55% maximum permitted for trucks 1990 and older.

“He passed, but this summer he would fail. Unofficially, the Ministere du Developpement durable, de l’Environnement et des Parcs (Ministry of Sustainable Development, Environment and Parks) is going to lower the maximum for 1990 and older vehicles to 40% and the maximum for vehicles 1991 and newer from 40% to 30%,” Yetman explained.

Had the truck failed, the fine would have been somewhere between $300 and $3,000. The fine doubles for owners or companies that re-offend within two years. Fines for running without a stock anti-pollution system or with a non-conforming system start at $750.

The driver, squinting and dusty, came back from the agent’s car. Rounding the hood of the International, he threw an indecipherable look over his shoulder at Yetman. After 20 minutes of this song and dance he must have been wondering, ‘When’s the hammer gonna drop?’ The agent stepped up to his window.

“Stay away from him for awhile,” he told Yetman, who in turn told me, “My colleague is not seizing the vehicle because the suspension is recent. We usually give the owner the benefit of the doubt for a few days.”

The agent escorted the truck to a parking lot a half-kilometre away. A half-hour and one more smoke test later, we packed away the gear and swung the hard cases into the patrol car. Cooling in the air-conditioning, we passed the International, the driver’s head tipped back half-way out the window, simmering under the white sun.