cycling to work

I have been cycling to work for the past couple of days and its been fun. Yesterday I rode in with an average speed of 15mph though my usual average has been 13.5-14.0 mph. Its about 4.5 miles to work from home and there are several lights that I have to wait at, then there are the two security gates on base.

My friend Pamela rides on the weekend and she claims an average ride speed of 16mph for rides of over 50 miles. I need to speed up to be that fast.