What is a good average mph for commute?

[cloggsy]

My PB for my 'normal' commute is 20.37mph. My 'normal' commute being 12.88 miles which I completed in 37:56.

My average is 18.76mph since I started riding again (back in April '11.)

 

[rowan 46]

40mph would be a good average speed for a commute. I am not saying it's possible but it is a good average