You are deciding whether to believe the 28 minutes the map shows between this house and your job, and what number to write in its place before you make an offer. The map is a model of a typical trip. You will drive a specific one, at a specific hour, in both directions, for as long as you live at this address and work where you work.
Drive it at the hour you would leave, drive it back at the hour you would come home, do it on more than one weekday, do it while school is in session, and do it once on the road the map did not pick. Write every run down. That table of minutes is the number you carry into every other decision about the house, and no listing or mapping app can give it to you.
What are you actually deciding?
The 25 minutes the map showed you on a Sunday afternoon is 47 minutes on a Tuesday in October when it rains. Both numbers are true. Only one of them describes your life.
The decision is which number you plan around. If you plan around 25 and live with 47, the 22 minutes you did not count arrive twice a day, every workday, in the two worst parts of the day. Run them through the formula in Commute Math: at 5 days and 48 weeks, 20 extra minutes each way is about 160 hours a year. If you plan around 47 and live with 47, you may have passed on a house you would have liked. Both choices cost something. Measuring costs you a trip and several early mornings, and it can turn a house you loved on Saturday into one you cross off on Tuesday. Trusting the map costs nothing today. It can cost you about 80 hours a year, at those same 5 days and 48 weeks, for every 10 minutes each way the map missed, and you find out after closing. If the map says 9 minutes on surface streets, one run will settle it. The method earns its mornings on the corridors where the map’s number and the Tuesday number can sit 20 minutes apart.
What the map number is, and is not
A mapping app with “depart at” set to the hour you would leave is an Estimate: a prediction of a typical trip, built from the traffic the app has seen on that road at that hour. Write it down for both directions. It is the first line of your table, and you label it Estimate so you do not mistake it later for something you measured.
The app has seen more trips on that road than you ever will, and on the average day it will land closer than your two runs. What it cannot see is your driveway, your parking space, the day a lane closes, the week the school year starts, and the game that empties the arena onto your road at 5:40. Those are where the minutes hide. The app measures pin to pin. You will be measuring driveway to desk.
The Census Bureau publishes average travel time to work by area from the American Community Survey (Official record, at https://www.census.gov/topics/employment/commuting.html). That figure is what the people in a county or a tract report, on average, about their own commutes, and it never describes your address, your employer, your hour, or your route. Use it to notice whether an area is a place where people drive far. Then put it down.
Drive it at the hour you would leave
Start at the front door of the house, at the minute you would leave on a workday. Drive to the entrance of the building where you work, park where you would park, and stop the clock when you are at your desk. Write down the date, the departure time, the route, and the minutes.
One run on one Tuesday tells you about one Tuesday, and the only cure is more runs. A scouting trip that lands on a school holiday, a Friday before a long weekend, a snow day, or the week after a road reopens gives you a number that is true and unrepresentative at the same time. Check the school district calendar (Official record, on the district website) and the state 511 site for closures before you decide what the run you made means.
If you cannot be in town on a weekday, you can still run the map at the right hour on the right day and phone someone who drives the road. That is an Estimate and a Local observation, and together they are better than the Sunday number. They are still not a measurement.
Drive it back at the hour you would come home
The evening drive is a different road. The bottleneck moves. The sun is in your eyes instead of behind you. School lets out at 3:15 and the buses are on the arterial. If there is a plant on the corridor, its shift change lands on your drive home. The morning run tells you almost nothing about any of this.
Time the return at the hour you would leave work, from the parking space to the driveway. If your day ends at 5:30 some days and 6:15 others, run both if you can, because the difference between them on a congested corridor can be larger than the difference between two houses. Each extra run costs you an evening on the scouting trip that you would rather spend walking the neighborhood, and that is what the second number costs you.
Drive it on a second weekday
Monday and Friday often behave differently from midweek, and the difference is local: in some metros Friday afternoon is the heaviest drive of the week, and in others it is the lightest because much of the office stays home. The map can show you the difference if you check it on both days. Knowing it takes driving both, or asking.
Run the route on at least two different weekdays. If rain is forecast on one of them, take the rainy day on purpose. Then assume the number has bad days your sample did not catch, because it does. Two runs cost two mornings, and a table with two rows is still a small table, but it is a table with a range instead of a single number, and the range is what you plan around.
Find out what school does to the road
School traffic is the variable a summer scouting trip cannot see. Bell schedules put a school’s worth of cars on the same roads at the same minute, and bus routes stop on arterials that were clear in July. A house that is 22 minutes from work in August can be 34 minutes from work on the first Tuesday in September, and the map checked in August did not know.
Check two things on the district website (both Official record): the academic calendar, to learn whether school was in session when you timed your run, and the bell schedules for the schools along your route, to learn when the pickup line forms. If your timing runs fall outside the school year, you have a gap in the table that you cannot close yourself before the offer. Close it with a local. Ask someone who drives the corridor what 7:30 and 3:15 look like in October, and write that answer down as Local observation, next to your own runs, not in place of them.
Drive the route the map did not pick
The app chooses one road and shows you one number. The road it chooses is the one that is fastest on a typical day. Your question is what happens on the day it is not, because a crash on a two-lane bridge at 7:50 does not care what the model predicted.
Drive the second route once, at the same hour. Note where it leaves the main road and where it rejoins. On an ordinary day it is slower, which is why the map did not pick it, and you may finish the run thinking you wasted a morning. You did not. What you learned is whether this address has an escape when the main road fails, or whether every route funnels through the same interchange. An address with one way out has a commute whose bad days run long, and no map shows you that number.
Check the state 511 traveler information site for the road while you are at it. The Federal Highway Administration explains the 511 system at https://www.fhwa.dot.gov/trafficinfo/511.htm (Official record), and each state runs its own site with current incidents, closures, and construction (Official record). If the corridor has a history of closures, the alternate route is part of your commute, and its minutes belong in the table.
Time the last half mile
The map stops at a pin. Your commute stops when you sit down. Between the pin and the chair is a parking garage entrance with a line at 8:05, a lot three blocks from the building, a badge gate, an elevator, or a daycare drop that turns a straight line into a triangle.
Time this piece separately. It is the part that does not change when you change houses, and you want to know how much of your total it is. If you do not yet know where you will park, ask the employer before you time the run, since a downtown office with a garage across the street and one with a surface lot half a mile away are different commutes from the same address. The daycare or school stop belongs in the table too, as its own line, because it happens every day and the map never included it. This adds rows, and each row is another number to keep, but a commute that is 28 minutes on the map and 41 minutes door to desk is a 41-minute commute.
Check what the road is about to become
The road you timed is the road as it is this month. State departments of transportation publish planned projects on their websites (Official record), and a corridor widening that runs for three years changes every run you made. Look up the route on the state DOT project list and the 511 site. If something is scheduled, ask a local what the detours look like, because the project page describes lanes and the local describes mornings. The list shows what is funded and dated, and a project can slip a year or stop halfway, so what you learn is that the road will change, and only roughly when.
If the route uses a toll road, find the tolling authority’s published schedule (Official record) and read what your hour costs, including peak pricing where it exists. Then drive the free alternative once and time it. The toll buys minutes; the free road costs them. You decide which you are paying with, but you cannot decide until both numbers are in the table.
Test the schedule you have, and the one you might get
Everything above assumes you know which days you drive. An employer’s remote or hybrid policy is Provider-reported. It describes this year’s arrangement, and a memo can end it. A commute that works three days a week from this address may not work five.
Run your table at the schedule you have, then at five days, and look at the annual hours both ways with the formula in Commute Math. If the five-day number is one you could not live with, you are betting the house on the policy holding. Some people take that bet with open eyes and win it. Make it on purpose.
If you ride transit, the agency’s published schedule and service alerts are Official record. Time the trip door to door, including the walk to the stop, the wait, the transfer, and the walk at the other end. The schedule shows the run time between stations. You are measuring the trip between your kitchen and your desk, and the second number is the only one you will live with. Riding it at your hour takes a morning of the scouting trip that you cannot also spend driving, so if you might do either, you are timing two commutes.
Put the measured number where the map number was
When you are done, you have a small table. Date, departure time, direction, route, minutes. Somewhere on it is the estimate you started with, labeled as an estimate. The rest is what you measured, plus what a local told you about the days you could not measure, labeled as observation.
Take the measured minutes into the annual-hours formula in Commute Math, in place of the map minutes. Take them into the Five-Places Test as the first and heaviest of your five trips, and into the comparison between this house and the other one. Every one of those calculations is only as good as the minutes you put in. The map’s minutes are the one input you can replace with something you know.
You will not get one number. You will get a range from a few runs, and a note about October from someone who lives there, and a second route with its own minutes. That is enough to decide with.
What must I verify personally
Before you make an offer on this address:
- Set the map to “depart at” your real departure time on a weekday and write down the estimate in both directions. Label it Estimate.
- Drive from the front door to your desk at that hour on a weekday. Write down the minutes.
- Drive back from your parking space to the driveway at the hour you would leave work. Write down the minutes.
- Repeat both runs on a different weekday. If rain is forecast, take the rainy day.
- Check the district calendar. If school was not in session when you drove, ask a local what the road does at 7:30 and 3:15 in the school year, and write the answer down as Local observation.
- Drive the second route once at the same hour. Note where it rejoins the main road.
- Time the last half mile separately: parking, the walk, the badge gate, the daycare stop.
- Check the state 511 site and the state DOT project list for construction on the corridor and how long it runs. Check the tolling authority for what your hour costs.
- Run the table at your current schedule and at five days a week.
- Put the measured minutes, not the map minutes, into the Commute Math formula.
What should I ask a local
- How long does the drive to that part of town take at 7:40 on a weekday, really, and which way do you go?
- What happens to that road when it rains, when school is in session, when there is a game, or when a lane closes?
- Where does traffic actually stop, and is there a way around it?
- Is there construction planned on that corridor, and for how long?
- Is the morning or the evening worse?
What should I ask my agent
- Which route did you time, at what hour, on what day, and how many times?
- Which of your recent buyers drive this corridor, and what do they say about it now?
- Will you meet me at the house at 7:15 on a weekday so I can time the run from the driveway?
The rest of what to check on the trip, beyond the drive, is in The Neighborhood Scouting Trip.
