This app was mentioned in 1 comment, with an average of 5.00 upvotes
Thought I'd also drop the app I use to make sure I'm not going over the egg hatching speed : https://play.google.com/store/apps/details?id=com.joynow.ecodrivefree
I use the free version, set the floating speedometer bubble to the top mid of my screen, activate the 'alarm' (more of a quiet beep really) speed so I'm not going over my speed, and let it run. Works great for what I use it for.