Can a car move on a banked road without friction? My information is very limited. All I know is that there is a normal force and gravity acting on the car. I know what a banked road is, I know a centripetal force is a force that tries to pull the car towards the center. However, I have tried researching and I can't seem to understand so please make me comprehend on this topic. I need it to be simple otherwise it'll be futile. English isn't my native language. Thanks in advance.
Can someone just tell me why friction isn't needed?
 A: The frictionless banked curve exerts a normal force $F_{n}$ perpendicular to its surface. The downward force of the gravity $F_{g}$ is present. The two forces add as vectors and the resultant or net force $F_{net}$ points toward the center of the circle. This is the centripetal force. 
 
When the forces are resolved into their components, you will find that $F_{net,y}=F_{n}\cos\theta-F_{g}=0$. Hence, $F_{n}=\frac{F_{g}}{\cos\theta}$. You will also find that $F_{net,x}=F_{n}\sin\theta$. You know that this is equal to the radial force, $F_{r}=m\frac{v^2}{r}$. 
$$F_{r}=F_{net,x}\Longrightarrow\frac{mv^2}{r}=F_{n}\sin\theta\Longrightarrow\frac{mv^2}{r}=\frac{F_{g}}{\cos\theta}\sin\theta\Longrightarrow\frac{mv^2}{r}=mg\tan\theta\Longrightarrow\frac{v^2}{r}=g\tan\theta$$
After simplifying, you will find that $v=\sqrt{rg\tan\theta}$, where $\theta$ is the angle that will allow a car to travel on a frictionless curve of radius $r$ with constant speed $v$. A banked curve is designed for one specific speed. Traveling at a speed higher than $v$ means the car will slide out, up, and over the edge. Traveling at a speed lower than $v$ means the car will slide in, down, and off the bank. 
A: Cars are complicated; don't let the complications distract you. Go in your kitchen and get a big mixing bowl and an ice cube. 

Hold the ice cube in your hand a moment until it goes from sticky-cold to damp-cold. Now it's melting, and it'll separate from whatever surface it touches by a thin layer of water. This is basically an ideal low-friction interface.
Give the bowl a shake, and you can get the ice cube to slide around the bowl in a circle.  Once it's going, it'll go for a pretty long time in a level circle. The faster the ice cube is going once you get it level, the higher up in the bowl it'll ride --- because the bowl is more steeply sloped up near the rim than it is near the base.
This should make it clear that an object can use a banked curve to follow a circular path even with negligible friction. You have other answers that get deeper into the the vector arithmetic of why.
A: For movement of a car on banked road, all you need is a component of any force towards center of circle.
If you find that friction is not present that means that a component of normal reaction acting on the wheels of the vehicle is present in the radial direction and is enough to sustain the circular motion of the vehicle without the need of friction.
