How can I detect potholes using an accelerometer mounted in a vehicle? I am currently studying DSP and FFT, I am very new to this and have been doing electronics for a long time with Arduino and hobby projects. Recently, I am doing a project with the goal to map potholes along your daily commute in the car, measuring road roughness. This is not the road profile, but the subjected roughness of the ride the driver feels during the trip. I have an acceleration mounted to measure Z-axis "vertical" acceleration of the car, when a pothole is struck the shocks and springs dampen the force as per the quarter car model for simplicity.

Basically I want to be able to create a detector that will detect potholes by using FFT to find the dominating frequency of the vertical acceleration, then I can maybe match it to pattern to detect door slamming of the car door, or a man-hole cover from a pothole maybe in the future. 

I'm not sure if FFT is the way to go, any input or advice and ideas are greatly appreciated, I have made a low pass filter to filter out the higher frequency vibration from the drive train and engine.

Any ideas on the subjected "roughness" felt by the passengers/driver in the car? I was thinking of doing road tests on a smooth road, gravel road, brick road, bad road, and coming up with a threshold of the magnitude of the vertical acceleration and making a scale somehow on what is considered "rough"

The potholes detected would be also logged with GPS their locations, I'm trying to use the Rasberry Pi for this, with data storage and its speed as a good project for it.

Thanks any help or ideas is appreciated, books, tutorials, wisdom, etc

UPDATE:

Carry over additional data here:

https://electronics.stackexchange.com/questions/56238/accelerometer-data-smoothing-filtering-pothole-detection
You are not really interested in the frequency information in your signal so much as detectable features - as such I would suggest that there isn't that much utility in an FFT here.

What you really want to do is correlate the continuous 'car signal' recorded in the car with a different signal which is the 'signature' of the pothole bump. You will need to acquire this signature by recording it in a car going over a pothole (perhaps recording many and using them to produce a generic signal which is a good representation of a pothole). Once you have it you can cross correlate it with your car signal. You may want to do this in the frequency domain in which case you should cross correlate the FFT of your signature with a sliding FFT of the car signal.

You may want to process the car signal before you use it to remove, for example, high frequency noise (with a lowpass filter). You can do this pretty effectively by eye - play around with various filters on car signals to see which removes the most extraneous information while leaving the important pothole information intact.