A traffic prediction is most useful as a range, not an exact promise. Compare several departure times, protect the required arrival time with a buffer, and check live incidents shortly before leaving.
Work backward from the real arrival requirement
Start with the time you must be inside the destination—not the time you want to reach its street. Subtract parking, walking, security, check-in, and a delay buffer. That produces the latest acceptable curb-arrival time.
Leave-by time = required arrival − parking and walking − expected drive − uncertainty buffer.
Compare at least three windows
- Request the route for your preferred departure.
- Check one time 15–30 minutes earlier.
- Check one time 15–30 minutes later.
- Record both the estimated duration and the route chosen.
Google Maps supports Depart at and Arrive by estimates for eligible single-destination routes. Its directions guide explains that estimates use traffic for the planned time. Apple Maps also allows a future leave or arrival time and notes that predicted travel time can change.
Look for the shoulder of the peak
The goal is not always the earliest departure. Look for a window where predicted travel time drops without creating an impractical wait at the destination. A small shift that avoids a recurring school, commuter, event, or construction surge can be more reliable than a larger detour.
Add a buffer that matches the consequence
| Trip | Buffer approach |
|---|---|
| Flexible errand | Small buffer; recheck before leaving |
| Appointment or airport | Include parking, access, and a larger incident allowance |
| Multi-stop schedule | Protect the first fixed stop and add recovery time later |
| Severe weather or major event | Use official guidance and consider changing the trip |
Recheck live conditions
Predicted traffic cannot know every crash, closure, weather change, or event. Shortly before departure, compare the planned route with live traffic and the responsible road agency. If the route changes, confirm that the new road and destination entrance are suitable.
Keep a small record for recurring trips
For one week, note departure time, predicted duration, and actual duration. A few observations from the same weekday and season are more useful than a generic rule such as “always leave before rush hour.” Do not collect these notes while driving.
Related guidance
- Understand why an ETA changes during the trip
- Read live traffic colors in context
- Add time for construction safely
Reviewed July 19, 2026. Traffic predictions are estimates and cannot guarantee an arrival time.