Use gps tracker for blackberry. It tracks exactly how fast you are going every 2 seconds and records it on an online map that you can pull up whenever you want. Just sign up for the service (is free - just a login for your tracker map - www.instamapper.com) then remember how fast you were going past a specific point, IE through an intersection or on a specific street or from point to point. I don't have a speedo healer, but I use that program for all rides that way I have a record of where I was at and when and what speed - handy if I really enjoyed the route and want to cruise it again later.