APP for measuring timing GPS speed from a roll ?

[DroidGTI]

Hello,

I was wondering if anyone knows of an APP that is available to measure 40-60 mph or 20-50 mph times using a GPS signal and a simple timer ? So say I set my app to start timing when I hit 40 mph and then stop timing automatically when I hit 60 mph ?

I looked into the Adyno app, but its completely useless for those kinds of things and frankly stinks.

I see there are plenty of GPS apps, but nothing with a timer involved, anyone know of one?

Thanks!