Pros: Superior fuel economy, acceleration and responsiveness when properly tuned.
Cons: Pricey; can be clumsy at low speeds and when parking.
Summary: If you're shopping for a car and you see the term "automated manual transmission" (or sometimes "automated-clutch manual transmission"), it refers to a transmission that's mechanically similar to a stick-shift, except a computer performs the clutch work.
To be clear, an automated manual transmission (AMT) doesn't have a clutch pedal; there's only an accelerator and a brake pedal, just like a regular automatic. And if you leave an AMT in D mode, it basically performs like an automatic transmission -- all you have to do is worry about when to start and when to stop.
Accordingly, some AMT drivers may actually believe they're driving a traditional automatic. But there are some important differences that informed car shoppers should be aware of.
For background, there are two types of AMTs: single-clutch and dual-clutch. Single-clutch AMTs are older, lurch-prone and generally unpleasant; the good news is that only the smart fortwo and some exotic sports cars use them. Dual-clutch AMTs, on the other hand, are designed to eliminate lurching, and the best units provide incredibly quick yet perfectly smooth shifts. Most AMT-equipped cars use dual-clutch technology.
AMTs also tend to yield better fuel economy and acceleration than regular automatics. The reason is that AMTs are more efficient; that is, they allow more of the engine's energy to flow directly to the wheels. For the same reason, stick-shifts have historically edged automatics in both categories. The magic of the AMT lies in its ability to combine the fuel economy and performance of a true manual with the everyday convenience of an automatic.
AMT downsides are few but notable. First, the technology is complex, so you'll pay more up front -- and if the transmission goes bad out of warranty, you could be on the hook for an expensive repair bill. Also, engineers haven't quite worked out low-speed AMT behavior yet, so when you're nosing the car into a parking space, for example, you'll likely notice a "slip-and-surge" effect that's like being in a stick-shift car with a teenager learning to drive.
But overall, the AMT is a clear victory for automotive progress. We expect this transmission type to become increasingly popular as costs come down and consumers embrace its numerous advantages.
What it means to you: A thorough test drive is in order if you're considering an AMT-equipped vehicle, as transmission behavior can vary widely among automakers. But given the AMT's considerable upside, we encourage you to consider adopting this technology in your next car.