Method one: open the window to listen to whether the sound comes from outside the car; 
Method two: after improving the speed (when the buzz is larger) will gear in neutral to let the vehicle taxi, observe whether the noise comes from the engine, if there is no change in neutral taxi hum that is mostly the wheel bearing problem;
Method three: temporary stop, get off to check whether the temperature of the wheel shaft is normal, the method is: touch the four wheels respectively by hand, roughly feel whether their temperature is consistent (brake shoe, piece clearance is normal, the temperature of the front and rear wheels is a gap, the front wheel to high)