If they haven’t fixed the under inflation problem in 20 years, what makes you think more regulation will fix this supposed problem? Answer: either not a problem in the first place or a useless fix.
There is one thing this regulation fixes. In the US, rolling resistance values are not published. This regulation would change that.
In CA, the shop is required to check and adjust tire pressure and document it on the repair order any time a vehicle is in for any maintenance or repair, tire related or not. So your car could be in for wipers and a window switch and they have to tend to the tires.
I wonder if that has made an improvement?
They have; tires get inflated much more frequently with this regulation, saving fuel and reducing air pollution.
Removing inferior tires from the market should do the same.
Side note: this tread has had more than 500 views, replies from 19 members but only 10 people clicked on Barry’s link to review his summery on the topic. Is anyone interested in tires?
When reviewing service history on a customer’s car, I often see a separate repair line for inflating tires, an indication the customer visited a California dealer.
If a vehicle is in the shop for a recall or just a light bulb, I inflate the tires. Most other technicians do not, I see the complaints.
Improper tire inflation - over/under - remains a challenge to be overcome, everywhere, as evidenced in my deleted telling of my experiences in the Philippines.
It’s only not a problem inside forums such as CTCommunity.
It was our company policy (unless customer declined it) to wright down the in and out psi on every work order as well as tread depth in 3 places across the tread, yes a lot of techs would rubber stamp it, but the ones that did it found a lot of needed flat repairs… If a vehicle came in and 1 tire was 5ish+ psi over/under the rest of the tires, then we would look for the reason why…
There has been much talk about the Pros and Cons of the value of filing tires with Nitrogen… If the vehicle does have Nitrogen in the tires, are the tires in California noted with some “Nitrogen” symbol or is the owner expected to inform the service writer who just wrote a work order to replace the windshield wipers that the tires are filled with nitrogen and what then if the tires do need air and the service center does not service Nitrogen Tires… What then, refuse to service the customer’s car since the driver might be involved in a low pressure tire caused accident or make the customer sign a waiver of service?
Inquiring Minds Want to Know…
I think the whole thing is silly. It would make far more sense and cents to require cleaning the windshield or checking the oil. TPMs will now let you know if you have a low tire which is very handy. Don’t need no oil jockey messing with my tires or Tyres as they say in the uk.
Good question, not sure what California will require but our vehicles with Costco supplied tires with nitrogen have the green valve caps.
If the vehicle has green valve cap or green O-rings on the valve stems, the tires get regular compressed air unless otherwise requested by the customer. The amount of oxygen in the small volume of air added won’t make a measurable difference. I can add an additional 0.25 psi to compensate for the oxygen that will escape if that comforts the customer.
It is likely the green caps were installed while the previous set of tires were on the vehicle. Worrying about the small amount of air added to the tire is a waste of time. One out of a hundred customers might have a panic attack over “mixing” air. Relax, this won’t cause 7 years of bad luck.
With nitrogen, the tires are 3 psi low. With air, the tires are 6 psi low.
Nitrogen won’t harm the tires but driving with tires that are 6 psi low will.
There is a button on the steering column stalk to clean the windshield, and the oil level is checked each time the engine is started. My sons Pontiac had these features; maybe more cars will in the future.
Not yet! green valve stem caps are not legally required for nitrogen-filled tires. They are simply an industry-standard visual indicator used by dealerships and tire shops to remind you and other mechanics that your tires are filled with nitrogen rather than regular compressed air.
My truck cane with N2 (nitrogen) filled tires. Did I care? No, I filled them with “nitrogen blend”, normal atmospheric air. I changed out the valve stem caps.
The Green caps on the valve stems identifies the industrial standard the the tires have nitrogen in them… We were told to not add regular air to top off a tire filled with nitrogen, and if we needed to add air to a low tire to let all the air out (remove the Shredder valve) to remove the nitrogen and then just fill it up with regular air, install a normal black valve stem cap and hand the customer the green cap back…
That slowly faded away to nobody cared anymore and just added air when needed, to my knowledge, no tires blew up due to mixing the 2… But we still handed the green caps back when replaced by black ones…
The point I am making is that Nitrogen filled tires is one of the big up-sales for service stations and dealerships. Filling a set of 4-tires with nitrogen in California can run from $40 upwards to $200.
The membership has already established that the “sharpest” tool in the toolbox is not the tire service “technician”.
So, a “Pretty Green Cap” would not be much of a notice that the vehicle owner does not want you putting your “nasty, old, greasy compressor air” as a favor to top off the tires… Especially since there are so many colors of valve caps to choose to match your car’s color…
Last time I got new tires installed at Costco, they neglected to install ANY valve stem caps 
Perhaps the person that came up with that was thinking of evacuating R12 from the AC system
or they thought the nitrogen was nitroglycerin. Though I suppose there might be that tiny percentage of vehicle owners that would insist on using only nitrogen.
The reasoning never made much sense to me, but I followed policy until the policy vanished… lol
I think it was more for the customers state of mind than damaging the tire by mixing the two…
Probably more of a stable thing as the customer would have 1 tire that the pressure changed more than the other 3…
That money pays for suits and dress shoes. The working class doesn’t get paid for topping off tires.
It is very likely the mixture in the tires has been compromised over the years so why waste time using the nitrogen machine to add air? The customer must have added air to the tires at some point.
There are people who will only drink Civet coffee, who only use an iPhones, who only eat: Beluga caviar, white truffles, Ayam Cemani (black) chicken and who only put Nitrogen into the tires of their cars…
And they would go ballistic finging out that someone, not matter how well intentioned, put “common air” in their tires…
Everyone (that’s the rest of us…) knows that the only benefit to Nitrogen is that it is better than compressed air in tires primarily because its larger molecules leak through rubber roughly 40% slower, resulting in more stable, long-lasting pressure.