how long does it take for the avg, not so fit person to bike relatively flat surface...

[Lord_Darkclaw]

On a perfectly level and smooth road it would take you less than 30 minutes but figuring it some bumps and traffic and inclines you should expect it to take 1 hour on a reasonable quality bike.

The road may not be as flat as you think it is if you haven't cycled it before, up-hill sections that you would not even notice in a car can feel like mountains on a bicycle. If you get tired take a 10 minute break.

 

[John S]

...of 4 miles.? this is the distance to and from school, which I want to start biking.

 

[Bob A]

You should be able to ride at 12 mph on level ground.

 

[Lord_Darkclaw]

On a perfectly level and smooth road it would take you less than 30 minutes but figuring it some bumps and traffic and inclines you should expect it to take 1 hour on a reasonable quality bike.

The road may not be as flat as you think it is if you haven't cycled it before, up-hill sections that you would not even notice in a car can feel like mountains on a bicycle. If you get tired take a 10 minute break.