Unbalanced motors is one of the first issues to be addressed in the smart car. Thes 6 V motors are not made equal and pull different currents and rotate at different speeds. The video shows that the left wheel alone pulled 0.16 A, the right wheel alone pulled 0.14 A, both wheel together pulled 0.12 A from the battery pack. The result of this is that the wheels do not turn at the same rate. Moreover, the Arduino chip can only handle 0.04 A of current and would burn out if the motors were driven directly from the Arduino chip. So, the next task will be to measure the speed of each wheel and control their speeds so that the car will travel in a straight line when wanted. While the motor can be controlled using Arduino programs, a motor shield will have to be used to buffer the current capacity from 0.040 A to 0.16 A at least. The L293D chip is the remedy for this problem which is a electric buffer between the Arduino and motor that allow you to control voltage, current, and thus the speed of the motors.