KAYSVILLE -- Since Davis County Health Department turned over its diesel-fueled vehicle emissions testing to a private contractor on Jan. 2, the first-test fail rate on older, mid-sized diesel-fueled trucks has risen threefold.
The fail rate has gone from 8 percent in 2012 to 28 percent in 2013, drawing complaints from vehicle owners.
But the cause for the rise may be as simple as new state-of-the-art vehicle emission testing equipment, officials say.
On Dec. 31, 2012 the county got out of the business of performing vehicle emission tests, leaving the practice to the 125 privately owned service stations in the county.
But because of the subset of older, mid-size, diesel-fueled vehicles that remained in the county -- roughly 6,500 -- the health department continued testing those by hiring a private contractor to perform the work in a long-term cost-saving move.
Worldwide Environmental Inc., under the oversight of the county, performs the emission tests at the Davis County Testing Center, 20 N. 600 West, Kaysville.
"There are a certain number of diesels needing to come to the tech center," County Health Director Lewis R. Garrett said.
The diesel-fueled vehicles being tested there are 2007 or older models, or those that do not have an onboard diagnostics system station operators can plug into, Garrett said.
The contractor uses equipment that reads exhaust opacity levels with a laser rather than a light, Garrett said. The 12-year-old equipment the county had been using was light-based.
First-test failures from January to April 2012 -- in which 988 vehicles were tested -- totaled 81, for a failure rate of 8.2 percent, according to Jim Duckworth, I & M Tech Center supervisor.
First-test failures from January to April this year -- with 1,211 vehicles being tested -- totaled 340, for a failure rate of 28 percent, Duckworth said in an email to a disgruntled customer who wished not to be identified.
"The program is to get those trucks that are polluting" off the road, Garrett said. Air quality is a major public health concern among residents, and the No. 1 cause for the county's poor air quality is vehicle emissions, he said.
Vehicles having failed the first test are allowed to be brought back in for a free second test after the vehicle owner has had time to make some minor adjustments to the vehicle, such as changing out the fuel or replacing the air or fuel filter.
"Generally, it is an easy fix," Garrett said. Of those vehicles that receive the second free test, 92 percent pass, bringing the overall fail rate number well within the final 8 percent fail rate the county experienced when it was operating the program last year.
"The ones that fail are those vehicles that are not getting routine, easy maintenance," he said.
As more vehicles are tested, and owners make those routine maintenance adjustments, Garrett said, he would anticipate the 28 percent first-test fail rate will drop some.
More often than not, vehicle emission testing operators can tell whether a vehicle is going to pass or fail based on the amout of exhaust it emits when it first accelerates, said Dave Spence, Davis County environmental health services division director.
In the meantime, until owners of diesel-fueled vehicles get ahead of the learning curve regarding the change, some vehicle owners may continue to voice their displeasure.
"We have had a few complaints," County Commissioner John Petroff Jr. said of the failure rates.
But with a new contractor came new equipment, Petroff said, resulting in the program catching more emissions violations.