Car makers like Volkswagen should have an even tougher time cheating on emissions tests than they first thought. The Environmental Protection Agency has revealed that it'll include considerably more real-world diesel emissions tests as part of its improved inspections. The on-the-road testing isn't as sophisticated as what you'd find in the lab, but it should reduces the chances that companies will fudge results. Moreover, vendors won't get a chance at optimizing for the EPA's new tests -- it's keeping its exact methodology a secret.
This new approach will only be so effective. European standards are looser (automakers can use optimized, pre-production models), and there's pressure to lighten planned reforms. However, this could still do a lot to keep diesel designers honest. Unless they're willing to forego the US market entirely, they'll have to avoid defeat devices and anything else that wouldn't work on the street.
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