Final answer:
Computer-controlled automated manual transmissions are the most effective at reducing driver fatigue in highway trucks because they take over the gear-shifting process, minimizing the driver's cognitive and physical load.
Step-by-step explanation:
The question asks which transmission technology most significantly reduces driver fatigue in highway trucks. Driver fatigue can be influenced by the degree of effort and concentration needed to operate the vehicle. In the context of highway trucks, transmission systems play a key role in this.
Among the options provided, b) computer-controlled automated manual transmissions stand out as the most effective in reducing driver fatigue. Manual shifting requires constant attention and physical effort from the driver, which can lead to increased fatigue over long distances. Hydromechanical power shift transmissions, while smoother than traditional manual transmissions, still require driver input for operation. In contrast, computer-controlled automated manual transmissions (AMTs) remove the need for gear shifting from the driver's responsibilities, which can significantly reduce the cognitive and physical load, leading to reduced fatigue.
Advanced transmission technologies such as 7+ speeds, dual-clutch transmissions (DCTs), and continuously variable transmissions (CVTs) are known for their benefits concerning fuel economy and reduced CO₂ emissions. However, when it comes to driver fatigue, the automated nature of AMTs takes precedence in providing restful driving experiences, especially on long highway stretches.
In conclusion, the correct option for most effectively reducing driver fatigue in highway trucks is b) computer-controlled automated manual transmissions.