What is your opinion of this traffic law and auto mufflers?

@john65pennington While I don’t have an answer, I have to admit I checked out your question and got distracted by your new avatar! What a handsome dickens! Much better than the photo of the cop car (with or without a muffler).

Kyak8…u made me laugh.

In my state, we have environmental regs that limit the content of the exhaust. I think that if you are found to be in violation, you have a certain amount of time to fix it. My guess is that if a cop tickets you for smoke, you have to take your car to be inspected to see if you are actually in violation. If so, you need to get it fixed. I’m just making this up, of course.

I suspect they were worried about people using cutouts or otherwise modified exhaust systems to reduce back pressure. The law probably just means that whatever ingenious alterations in the form or placement of your muffler that you may think up, they better not result in too much noise or pollution.

As for why the law hasn’t been challenged, it’s probably because there are only two possibilities: the law prohibits something that is not possible in the first place (meaning the law effectively does nothing, giving no one standing to mount a challenge), or it prohibits something that is possible (meaning a challenge would have to show that the state overstepped its authority, which doesn’t seem to be the case here).

In California you can get a ticket for visible exhaust. In fact, people are encouraged to report smoking cars by calling 1 800 EXHAUST.

Laws are often written by people with no understanding of technology. For instance, most of what you see from a cars exhaust is often water vapor; I see that all the time, especially in the winter and/or from a car that has been running for less than a few minutes.

@zenvelo What of older cars? Do they not allow pre-OBDII cars in the state of CA? And Diesels must also be verboten, so I imagine that there isn’t much trucking there either :D

Irrelevant laws sit on the books for years and years all the time. As long as no one is trying to enforce a bad law, no one tries to fight it and get it changed. Why waste time on getting rid of a law, if no one is enforcing it anyway? The politicians have enough to argue about.

@john65pennington – I bet you’ve given out plenty of tickets for noisy mufflers and belching smoky exhausts :-p

One thing I forgot to mention was the subjectivity of “excessive” is so subjective that it really is legally unenforcable in the first place. I remember a little legal review that was done on twenty random cases of “excessively loud exhaust” in CA. Only one defendant was Caucasian, and the way the law was written, his was the only exhaust system that was actually illegal; the other 19 were victims of profiling.

The law needs to be rewritten and updated for the 21st Century. It is easy to measure noise now. You just need a standard, such as: the average of 4 readings when taken “X” feet in front, behind, and on both sides of the vehicle the sound pressure level shall be below “Y” db while idling at “Z” rpm.. It is not perfect but it is a darn good measure. Also there should be a max limit such as: No reading shell be more than “X1” db peak when measured “Y1” feet from the vehicle at any location.
As for the smoky exhaust, that is measured with an opacity meter. The readings are easy to do. For newer vehicles there are already standards set by the EPA. Clean diesels have all kinds of aftertreatment devices besides the muffler such as Diesel particulate filters, urea injection etc. Old vehicles will still smoke. If you are looking for a standard, how about specifying that the vehicle can put out no more than 5x the EPA standard that was in force when the vehicle was certified.
That will knock out the few, really big polluters that are putting out 1000x the limit while letting the typical well maintained vehicles gradually age out without causing undue hardship.

@jerv Older cars, pre-catcalytic converter, are exempted of course, although there have been programs to buy them back to get them off the road. And California has been working on getting diesel exhaust cleaned up, not only on trucks but on earth moving equipment and buses.

But, you won’t get a ticket if your vehicle is up to standard for when it was manufactured. Part of the ticket is a smog check requirement.

@zenvelo In WA, any vehicle over 25 years old is exempt from emissions testing. My car has a cat, but it’s 27 years old, so I don’t have to worry about it.

Then again, I hear CA is rough on car enthusiasts anyways.