It seems like almost every day I wind up behind a car at the stoplight which emits a large gaseous plume as it accelerates through the intersection. I quickly roll up all windows and press the recycled air button until they’ve sped off. Why don’t the police issue these drivers a ticket so they would do something about it?
because they’re busy picking the low-hanging fruit of writing speeding and seat-belt tickets. broken cars get a “defective equipment” ticket which can be vacated if the owner comes back with evidence the defect has been fixed.
Here in Texas we grant a low-income waiver to folks below the poverty line. Their car has to pass the safety parts of the inspection, but not the emissions test. As I understand it, we decided to overlook that small segment in favor of helping them stay mobile (and employed). It can be catastrophically expensive (for them) to fix the emissions equipment on an old car.
Maybe you’re behind someone like this?
Could also be where the car is from. Many states don’t have any emissions testing required. Here in Indiana, only two counties (by Chicago) require testing.
I wish they’d crack down on noise first.
Don’t know if it’s still the case, but in Maryland, if your car flunked emissions, you had to supply a receipt from a mechanic that you spent X amount of dollars trying to fix the problem but it just wouldn’t take. 
Michigan ditched emissions testing years ago. It was a waste of money. The newer cars passed anyway, and older cars that flunked the test were mostly grandfathered out of the requirements.
CA has a program whereby the owner is required to spend $X, then , if their income is low enough, the state will issue a voucher for the balance.
Unless the mechanic states that car’s emission-control system has been tampered* with, in which case the owner is on the hook for the entire bill. There is a program in which the State will buy the smoggiest cars.
- early on, there were theories that certain ‘smog stuff’ ‘robbed power’ and some removed them.
In Ohio, only two counties require testing, and exempt vehicles over 20 years old. Testing isn’t required in most states at all.
This. The EPA seta National Ambient Air Quality Standards (NAAQS), which define allowable levels of pollution over certain time periods (daily, annual, etc.). Most areas of the US are in compliance, but the few areas that exceed NAAQS are required to take steps to remedy the situation, and one of those steps may or may not be automotive emissions testing. Some places do a smog check when you try to register your car, but other places are starting to use roadside drive-by checks in which the system examines your exhaust as you zip by on the road. I’ve seen this system in Denver; As you might expect it’s not extremely accurate, so it’s used as more of a pre-screening system: if your car is found by this system to be dirty, you have to bring it in for a more accurate tailpipe-sniffing emissions test.
Usually if there’s a big nasty plume coming out of a vehicle it’s a big truck or some other larger vehicle. Busses often are nasty that way, in my experience.
Also, somewhat counter-intuitively, smoking cars will often pass an emissions test just fine. The smog tests mostly test for things that are invisible and odorless. The person administering the test is supposed to flunk a car for visible or smell-able smoke, but none of the testing equipment looks for it, so it’s not too difficult to slip by especially if it only obviously smokes intermittently.
I had a car that sent out a plume on acceleration. But the emission test was a steady speed. So it passed easily year after year until it hit the “vintage auto” age and no longer needed testing.
Note that the visible plume stuff and the stuff they test for aren’t really the same.
Also, the number of these cars isn’t really all that great so the total emissions from them isn’t much. Trucks, for example, do a lot more total damage.