Roadside exhaust sniffers caught almost 900 vehicles in Northern Va. last year

Evening rush hour traffic on I-66 westbound, as seen from eastbound lanes near Centreville, Virginia. (Creative Commons/Flickr)

Little green boxes placed on roadsides around Northern Virginia to automatically sample passing vehicles’ exhaust generated just under 900 air quality violations last year, which are mailed to the offending vehicle’s owner along with a photo and instructions to make repairs or face a fine.

The program is part of an effort to improve air quality in the region that began in 1982 and requires emissions inspections every two years for certain vehicles in Arlington, Fairfax, Loudoun, Prince William, Stafford counties and the cities of Alexandria, Fairfax, Falls Church, Manassas and Manassas Park.

The boxes, a relatively new addition that relies on infrared and ultraviolet beams to test individual vehicles’ exhaust as they pass, serve a dual purpose: if a car passes the sniff test, it can count as the required emissions inspection. But if a car doesn’t pass, it requires owners to make an immediate fix.

“By identifying high-emitting vehicles between their regularly scheduled emissions inspections and requiring them to be repaired ahead of their next biennially required test, the high-emitter program causes owners to fix offending vehicles faster than they otherwise might,” said Department of Environmental Quality spokeswoman Irina Calos.

Some of the locations are advertised as automatic emissions testing locations, branded RAPIDPASS.

Others are not advertised “to aid in enforcement and program evaluation,” Calos said.

DEQ began testing the technology in 2004 and began using it for enforcement in 2006. Its current iteration, with advertised RAPIDPASS testing locations, began in 2016, which Calos said “may have led to a renewed public interest in the program.”

The unadvertised enforcement element of the program appears to have largely escaped public notice, although a muscle car owner warned his fellow enthusiasts online back in 2013 that he’d seen “sniffer vans at random on ramps” in the area. He said his strategy was to “coast by with my Jeep shut off after I pick up some speed.”

DEQ, which says it indeed used the vans in the early years of the program, estimates the identification of gross violators last year resulted in annual emissions reductions totaling 127 tons of carbon monoxide, 14 tons of hydrocarbons, and 36 tons per year of nitrogen oxides.