* Higher fuel economy: The engine runs at lower RPMs at highway speeds, conserving fuel.
* Quieter operation: Lower engine RPMs mean less engine noise.
* Smoother driving: Less engine vibration at cruising speeds.
However, overdrive isn't always ideal. It may be less efficient for accelerating, climbing hills, or towing. Many cars have an overdrive "off" switch (often a button or a position on the gear selector) to disengage overdrive when needed for these situations. If you feel the car is struggling in overdrive, using the "off" switch may be helpful.
