How accurate are drive-time estimates?
Every minute count on this site is a road-network estimate, not live traffic. When that is close enough, when it misleads, and how to check the times that matter.
A site whose entire claim is measured location owes you a straight answer about how the measuring works — and where it fails. Here is ours.
What a road-network estimate is
The road network is a graph: segments with lengths and typical speeds, joined at intersections. An estimate finds the fastest path through that graph and sums the segment times. It describes a typical journey on an ordinary day — not your particular Tuesday, not the monsoon burst, not the morning a wreck closes two lanes of the 10.
That is what every isochrone tool and most commute filters compute too. The alternative — live traffic — answers a different question: not "what is this route like?" but "what is it like right now?" Useful for driving; nearly useless for comparing homes, because "right now" is never the hour you asked about.
When the estimate is close
Off-peak, on freeway-dominated routes, across Phoenix's predictable arterial grid, road-network estimates land near reality. A Saturday-morning number or a 1pm number is usually trustworthy as stated.
When it misleads
The error is not random — it is systematic, and it flatters congestion. Peak-hour trips take longer than the typical-day figure, the inbound morning direction suffers more than the outbound, school zones add minutes at exactly the hours parents drive, and corridors near the airport and the stadiums have event patterns no typical-day model carries.
The practical consequence: two homes on different corridors can carry equal estimates and be genuinely unequal at 7:45am, because one corridor congests badly and the other does not. The estimate cannot see that difference; you can, but only by checking.
The rule of thumb we use
Treat a five-minute difference between two homes as noise. Treat a fifteen-minute difference as real. In between, let the rest of the picture decide. Estimates are excellent at ranking and shortlisting — that is what the Proximity Score is for — and merely decent at promising you a specific Tuesday.
Check the times that matter
For the final two or three homes, stop estimating. Put each address into a mapping app at the hour you would actually travel — that is live data, and no tool in this category matches it for a handful of routes. Better still, drive the winning commute once at your real departure time before you sign anything. One rush hour of evidence outranks every model.
Why estimate at all, then
Because comparison needs consistency. Scoring hundreds of homes against a ranked list of the places you actually go requires measuring every home the same way — and a consistent estimator compares homes fairly even where its absolute numbers drift. Use the map to get from a metro to a shortlist; use rush hour to get from a shortlist to a decision.