Yes, it's standard -- required by federal law (USA) in all cars since September of 2002.
ISOFIX and LATCH are basically the same thing, LATCH being the term most used in the USA.
"As of September 1, 2002, child restraints and vehicle were required to provide LATCH attachments (FMVSS 213) and anchors (FMVSS 225)."
Edit: The "top ten list" of cheapest cars to own over 3 years seems to be appearing on Prius questions a lot lately. It's written by Road and Track, and linked to by Yahoo! However, that list is irrelevant to anyone interested in a Prius (i.e., someone wanting a well-equipped midsize car that gets exceptionally great mileage). Here's the list with suggested retail price and mileage. Cheapest car to own over three years is #1.
10. Hyundai Elantra, $14865, 29mpg
9. Kia Forte Sedan, $14390, 28mpg
8. Suzuki SX4 Sedan, $14094, 26mpg
7. Kia Soul, $13995, 28mpg
6. Toyota Yaris Three-Door Hatchback, $13355, 32mpg
5. Kia Rio Sedan, $12390, 31mpg
4. Chevrolet Aveo Sedan, $12685, 30mpg
3. Smart Fortwo Coupe, $12635, 36mpg (premium gas)
2. Hyundai Accent Three-Door Hatchback, $10690, 31mpg
1. Nissan Versa 1.6 Base, $10710, 29mpg
So there you have it. Ten econoboxes all priced under $15K. Not the market that the Prius competes in. In spite of that, the Prius gets 38% better mileage than the best mileage car on the list (Smart Fortwo 36mpg vs. Toyota Prius 50mpg) and the Smart requires premium gas.
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