Air quality officials approved revisions to make tackling vehicle emissions on the Front Range more efficient.
The revisions change testing requirements for heavy-duty trucks, create stricter standards for diesel vehicles and add a shiny new option to take care of testing: self-service kiosks.
The kiosks will be available starting in 2026. Kiosks provide on-board diagnostics tests, a current requirement for cars built eight to 11 years ago and a new requirement for heavy-duty trucks. The division did not say where or how many kiosks will be installed.
The main goal is to increase customer convenience, said Steve McCannon, the mobile sources program director for the Air Pollution Control Division.
But the kiosks have some shortcomings — like not being able to test for gas cap leaks — that will be offset by stricter heavy-duty truck and diesel testing requirements.
Vehicle emissions contribute significant pollution to Colorado’s air, emitting tons of volatile organic compounds and nitrogen oxides, so-called ozone precursors that can combine in the summer to create smog.
While the state has been pushing consumers toward zero- and ultra-low-emission vehicles through stackable incentives, those efforts only apply to cars purchased in the past year or so. And while electric vehicle uptake has been hot and fast, there are many more people who aren’t on the market to replace their gas- or diesel-powered vehicles. That transition could be “generational,” McCannon said at an Air Quality Control Commission meeting earlier this month.
In the meantime, the commission wants to clean up cars that can be cleaned up, and catch the ones that can’t.
It’s all about the air
Last summer, a nine-county swath of the Front Range and Denver metro area violated ozone levels 40 times during the ozone season.
It’s one of 46 areas in the country that is currently out of compliance with EPA limits — a status called “nonattainment” — and the only area in Colorado in violation.
The region has been trying for decades to wrestle ozone levels down by strengthening air permit policies, regulating the oil and gas industry, setting city-specific carbon reduction goals, incentivizing companies to convert to hybrid or electric vehicle fleets, and even attempting to ban gas-powered leaf blowers and lawn mowers.
But the air pollution is stubborn, and the area is backsliding. The region’s violation was considered “marginal” by the EPA’s 2015 standard, but in 2022 the area was bumped up to “moderate” severity for failing to shore up ozone levels by a 2021 deadline.
Last year the state lost more ground, entering the “serious” classification, which is both a measurement of air quality — averaging 93 to 105 parts per billion of ozone over an eight-hour period — and a strict set of rules. The northern Front Range counties now are required to use more expensive gasoline that has lower emissions, and more businesses must obtain permits from Colorado Air Pollution Control.
The way things run now
Gas-powered vehicles, as opposed to diesel vehicles, are subject to different menus of emissions tests depending on the age of the car.
Cars between 8 and 11 years old get an on-board diagnostics test, which monitors emissions by checking signals from the car’s software. Older vehicles either receive an IM240, sometimes called the “treadmill test,” where a car is put on rollers to test emissions, or a two-speed idle test.
Revisions to the gas-powered program will affect two groups: heavy-duty trucks and cars that are 8 to 11 years old.
The kiosks will allow about 350,000 of the roughly 1 million vehicles that require testing on the Front Range to forgo a visit to one of 18 brick-and-mortar Air Care Colorado locations, or drive through an on-road remote sensor.
The downside to the kiosks is that they won’t measure gas cap leaks, which will result in an estimated release of 0.16 tons per day of additional hydrocarbons.
The division plans to offset those losses by changing the required tests for heavy-duty vehicles — trucks with a gross weight between 8,500 and 14,000 pounds — by switching newer models to the on-board diagnostic test from a two-speed idle test.
This change will save an estimated 0.09 tons of hydrocarbons, along with 0.96 tons of carbon monoxide and 0.09 tons of oxides from nitrogen per day — which the two-speed idle test does not capture — resulting in a net emissions decrease, according to the division.
Skirting the system
The heavy-duty truck change also helps identify vehicles that have been tampered with — an issue that McCannon was enthusiastic about taking on.
Vehicle tampering includes deliberately removing components that filter toxins from exhaust — for things like “rolling coal,” intentionally spewing clouds of black exhaust fumes from diesel vehicles — or adding components that cheat emissions tests, like the devices that Volkswagen illegally installed on its “clean diesel” vehicles and was punished for in 2015.
A Colorado Senate bill in 2022 gave the division authority to go after shops providing these modification services.
“It’s one of our favorite things right now,” McCannon said at the meeting about investigating tampering.
“We got resources, which was important,” he said of the bill. “So we have a complaint system, and we are getting complaints, and we are going out there and finding shops that are doing this. The EPA was out for a little bit, they have law enforcement authority so we were able to go out and actually walk onto facilities, which was exciting.”
Changes to the diesel testing requirements will also create more thorough inspections to identify vehicle tampering, and give testing centers more authority to approve or deny engine swaps — something that owners will do to improve performance or upgrade outdated parts, but that can occasionally constitute tampering if emission controls are removed.
However, McCannon noted that they still won’t have a good way to catch vehicles with software switches, or ways to toggle between regular exhaust output and rolling coal.
For what it’s worth, rolling coal has been illegal in Colorado since 2017, but reporting by CPR shows that as of August 2024 only 43 citations have been issued in the seven-year period.
The revisions also make it so all diesel vehicles must pass a 20% opacity test, which measures how clean exhaust is based on its opacity. Prior to the change, opacity could range from 20%-40% to pass depending on the vehicle.
Finding an inexpensive fix
Colorado has tried various incentives and waivers to encourage compliance with emissions testing. Last year a failed Senate bill would have offered $850 vouchers for repairs after a failed emissions test.
The state does offer three types of waivers for vehicle owners who can’t afford to pay for the repairs, or have made a good-faith attempt to repair the vehicle but fail a second emissions test.
“That’s a wonderful policy from an environmental justice standpoint,” said David Sabados, spokesperson for the Regional Air Quality Council. “But it doesn’t do anything for air quality. So that’s where we come in.”
Last year the council launched the Clean Air Auto Repair program, which offers zero-cost repairs for vehicles that fail emissions tests in a seven-county Front Range area. The program is similar in nature to the one proposed in the legislature last year, in that it accounts for economic hardship without letting dirty cars continue to drive.
The program builds off a smaller, more limited program that the council ran previously, and is able to offer a wider range of repairs, including catalytic converter and oxygen sensor replacements.Sabados hoped to expand the program beyond the 103 cars that were serviced last year, but the Trump administration’s federal funding freeze threw a wrench into their plans. He said that they are still accepting applications, but that the program will be “somewhat paused” until they determine whether the freeze will affect their program.