I need to track roads and later vehicles in an aerial video[snapshot in description] how to approach the problem?

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I would say to try to detect the road with a linear Hough transform, then extract the pixels that belong to the road. If it's done, you're halfway there.

Then, do a segmentation. You can use k-means or an adaptative thresholding to segment the "things" on the road. Do some erosion/dilatation to get rid of the noise. Now, you should have the silhouettes of the vehicles.

Finally, use a Kalman filter to track the movement of the objects.

Hope this helps.