Why Your GPS ETA Jumps

Your GPS says ten minutes. Two lights later it says thirteen. Then it says nine.

That jump feels wrong. Here is the truth. ETA is a guess, not a countdown.

First, the GPS uses a typical time. Then it adds extra time for delays

it cannot see yet. That is the math: average plus buffer. When traffic clears, the buffer shrinks.

So the number drops. When uncertainty grows, the buffer grows. So the number rises.

Quick tip. Trust the ETA more when you are closer. The system refines predictions as it

gathers real data from your actual drive. Early estimates include wider margins

because anything could happen. But those final miles reveal the truth.