What are the main differences between a hybrid and a conventional car?

Some of features that differentiate a hybrid from a conventional vehicle are:

Electric Motor Drive - Usually the motor(s) are used to drive the vehicle at low speeds where they are more efficient than a ICE. The motor also provides assist to the ICE for acceleration, passing or hill climbing. This allows a smaller ICE to be used. The motor is typically sized only to get the vehicle up to about 25 miles per hour and to cruise at that speed. Only 10-15 miles may be driven at that speed in the all electric mode.

Regenerative Braking - The electric motor shuts down during braking and coasting. Then the wheels drive the motor and the motor acts like a generator, charging the batteries.

Automatic Start/Shutoff - The engine automatically shuts off when the vehicle comes to a stop. The motor starts when the accelerator is pressed to start up again. The division of power between the engine and motor is controlled by a computer to balances the power as needed.

Internal Combustion Engine - The ICE is usually smaller than the engine in a conventional car because it is not used as much for acceleration. Only the ICE is used to power the vehicle at cruising speeds. The motor comes on to assist it during passing or hill climbing, if there is a demand for it. A portion of the engines power is also used to charge the batteries if needed.