Cars in cities. Do we really need them?

All over the world people use cars. They are comfortable and fast. Almost no one can imagine life without them. But sometimes people forget that cars are very dangerous for the environment.
We use cars everyday: when we ride to work, school or shop. Sometimes we use them too often. Why we don't use bicycle instead car? Bicycle is cheaper and it's less harmful for environment. Moreover bicycle is so much better for our healthy than car.
However old people can't use bikes. In this situation car is irreplaceable.
In my opinion people should use cars only for a long trip. When people want move on in town should use bikes or buses.
To conclude, cars aren't need all the time, but sometimes are irreplaceable. In my opinion people should use cars only for long trip. When people want move on in town should use bikes or buses.
Personally, I prefer bike than car because it's funnier and healthier.