| Automobiles made in the past decade or so are very | | | | to a halt. Using a technique known as engine braking, |
| different from the cars that were on the roads not | | | | the automobile's transmission can contribute to |
| long ago. The introduction of computer-based | | | | stopping force. In short, engine braking works by |
| systems has revolutionized car design, allowing all of a | | | | shifting into a lower gear. This increases vacuum |
| vehicle's systems to respond more intelligently. When | | | | pressure in the engine, causing the engine and the |
| something fails to work correctly, such as a vehicle's | | | | wheels to turn more slowly. |
| accelerator, the vehicle's other systems try to | | | | Engine braking is a familiar technique for people who |
| maximize the driver's control. Unfortunately this does | | | | frequently drive vehicles with manual transmissions. |
| not always work as planned. | | | | Many people who do not ordinarily drive vehicles with |
| Transmissions exist to control the relationship | | | | manual transmissions may be not be aware of engine |
| between the power generated by the vehicle's | | | | braking and how it works. Most recent-model vehicles |
| engine and the force applied to the wheels. Low | | | | with automatic transmissions already automatically |
| gears maximize the engine's ability to pull weight, | | | | utilize engine braking. |
| such as when climbing a hill, but it is much more | | | | For drivers of vehicles with automatic transmissions |
| difficult to go fast. Shifting into a higher gear means | | | | that already use engine braking, an engine that is |
| having less "pulling" power, but allows a vehicle to go | | | | accelerating out of control cannot provide any |
| faster when it is already moving. | | | | additional braking force. A malfunctioning acceleration |
| In newer vehicles, pressing the brake pedal has no | | | | system simply negates the vehicle's braking system's |
| direct effect on the brakes. Instead, the position of | | | | ability to utilize engine braking, and therefore reduces |
| the pedal instructs a computer to apply braking force. | | | | the driver's odds of bringing the vehicle under control. |
| The computer then triggers the vehicle's brakes as | | | | A number of recent-model Toyota vehicles have |
| necessary, changing the braking force on each wheel | | | | been linked with sudden uncontrolled acceleration. |
| to match road conditions. In vehicles with automatic | | | | Drivers of newer vehicles may be at risk of |
| transmissions, the computer may also use other | | | | experiencing Toyota sudden acceleration -and if they |
| sources of braking force. | | | | do, their brakes may not work as effectively as they |
| A vehicle's transmission can also be used to bring it | | | | should. |