How to convert accelerometer data into meter/second^2?

Question

I want to Convert accelerometer reading in x,y,z axis into acceleration in meter/second^2.I am developing a windows phone application to calculate the distance traveled by a taxi.I have already gone through some of links like

1. My Algorithm to Calculate Position of Smartphone - GPS and Sensors
2. Calculating distance using Linear acceleration android
3. http://blog.contus.com/how-to-measure-acceleration-in-smartphones-using-accelerometer/
4. Distance moved by Accelerometer

5. iphone accelerometer speed and distance

   But I didn't get any idea about exact way to convert acclerometer reading to acceleration.I know this reading is not accurate,But for me this is fine for now because I am considering only long distances.Please see the below mentioned code to find what I am trying to achieve

   private void CalculateAcceleration(AccelerometerReading accelerometerReading)
   {
        Vector3 acceleration = accelerometerReading.Acceleration;
        double xValue=acceleration.X;
        double yValue=acceleration.Y;
        double zValue=acceleration.Z;
        double accelerationInMeterPerSecondSquare="do something";
   }
   

   or some can please suggest some methods to calculate distances travelled from accelerometer readings

   I know I am poor in english.So I apologize for that. Thanks in advance.