Vehicle drivability is defined as the smoothness of a vehicle's operation at the will of a driver under all driving conditions. Currently, drivability evaluation is conducted through a subjective ratings-based test standard which is derived from established procedures. Human subjective rating can be inconsistent due to physical health conditions and individual preferences. This study is conducted to determine the possibility of using longitudinal acceleration to arrange an objective drivability assessment. Vehicle evaluation is conducted to determine the subjective vehicle drivability ratings of four drivability expert evaluators. A test vehicle was evaluated under different acceleration conditions to determine a subjective drivability rating. Vehicle low speed passing acceleration during pedal tip in is measured. A relationship between low speed passing acceleration and subjective drivability rating is established. An objective drivability assessment tool is successfully arranged using this relationship. A drivability rating can be generated using the tools, without the need for subjective evaluation by expert evaluators.

Vehicle driveability defined as smoothness of a vehicle operation at the will of the driver under all driving conditions. Driveability evaluation is conducted by giving subjective rating based certain test standard procedures. A group of test evaluators performed driveability test and gave individual rating based on subjective feeling. After discussion, a final overall rating is generated with consensus from all evaluators. Human subjective rating can be inconsistent due to physical health condition and individual preferences.Vehicle's acceleration profile can be associated with second order response. Every acceleration profileshas specific damping factorandnatural frequency.A study is conducted to determine the possibility of using second order parameter to setup an objective driveability assessment. Test vehicles with different acceleration conditionsare evaluated to determine driveability subjective rating. Acceleration profile for each vehicles is analyzed to determine its damping factorand natural frequency. A relation of damping factorand natural frequency with subjective driveability rating is established. The established relation of driveability is essential in providing guideline for future ECU calibration and tuning.