You can use this App if you are driving car.

Ever want to let the phone answers the call automatically when you are driving, or riding a bicycle, or busy doing something with both hands, or simply don't want to press that little button because your hands are dirty, then this app is for you. "Smart Answer & Callback" does only one thing and it does it well, it auto answers your calls for you so now it can truly be called "hands-free". Even more, it can also detect that a Bluetooth hands-free device is connected and automatically enable the auto answer, then disable auto answer when the Bluetooth device is disconnected. Program features: - Auto answer, if the call is in your contacts. - Auto callback to selected call. - Call to the selected. - It works only when a headset is connected. - The task execution delays.