and also for 1/4 mile times.
i installed one and clocked my car at 14.68 at 106mph in the 1/4.
however, i also had to push the damn button on the phone to start it and I spun a lot. so, if those two are figured it may be close.

are there any that sense the start of motion or movement of the gpps that are accurate?

 

I have pocketDyno, haven't actually had a chance to test it but it does have an option for a countdown start.

 

I've had good luck with Dynolicous

 

Subscribed

 

That would be a worth while app to have.
Back in the day we had a straight stretch of largely unused road where we had a 1/4 marked and your buddy in the passenger seat would click a stop watch. It wasn't extremely precise but it would get you in the ball park. Stone age technology for stone age cars.