A drive time is only true for the hour it was measured. If your schedule uses one number for a route all day, it will be right at midday and wrong in both rush hours, and the errors land on the first job of the morning and the last job of the afternoon.
Here is how to see it in your own day, put numbers on it, and plan around it.
The same 12 miles, three times a day
Take one drive: 12 miles from a job on the north side to a job across town. At 10 a.m. it takes 20 minutes. Most scheduling tools, and most dispatchers' heads, store it as "20 minutes".
The Federal Highway Administration measures congestion with a Travel Time Index: "The ratio of the peak-period travel time to the free-flow travel time." Its Urban Congestion Reports compute it for "the AM peak period (6 am to 9 am) and PM peak period (4 pm to 7 pm) on weekdays" (FHWA documentation, as of October 2026). A Travel Time Index of 1.3 means a trip takes 30% longer in the peak than in free flow.
So the drive is a function of the hour:
Peak drive = Free-flow drive × TTI
The index values above are made up for illustration. Your metro and your routes will have their own. The method is what matters: a 20-minute drive scheduled at 4:30 is a 32-minute drive, and the schedule has quietly lost 12 minutes.
Where the minutes go missing
Twelve minutes on one drive doesn't sound like much. The problem is where it lands.
The first job of the morning. The first drive is usually the longest drive of the day, from the shop or the tech's home, and it happens inside the AM peak. If it's planned at midday speed, the first arrival is late before anyone has done anything wrong. Every later job inherits it.
The last job of the afternoon. A 3:30 job that runs 30 minutes long pushes the drive to the 5:00 job into the heart of the PM peak. The overrun and the traffic stack. This is a big reason the last stop of the day has the worst on-time record, and why arrival windows get wider as the day goes on.
The drive home. A tech who finishes at 4:45 and faces a 40-minute peak drive back is on overtime or nearly there. That time is real cost, the same windshield time as any other drive, just paid at a worse rate.
Planning with the hour, not the average
You don't need a traffic model to start. You need to stop treating a drive as one number.
1. Mark the peak hours on the board
For most metros, the FHWA's peak periods are a fair starting point: 6 to 9 in the morning and 4 to 7 in the evening on weekdays. Any drive that starts inside those hours gets extra time. Any drive that crosses a known choke point (a bridge, a single highway between two parts of the territory) gets more.
2. Keep long drives out of the peaks
Two jobs 25 minutes apart at midday might be 40 minutes apart at 4:30. If the board has a choice, put the cross-town move in the middle of the day and keep the morning and late-afternoon jobs close together. A tight cluster of nearby jobs is barely affected by traffic. A long hop is affected a lot.
Fourteen minutes a day per tech, across 10 techs and about 240 working days a year, is 14 × 10 × 240 ÷ 60 = 560 hours. Run it on your numbers with the windshield time cost calculator.
3. Time the first job from the real start and the real hour
If your techs take trucks home, the first drive starts from home and runs in the morning peak. If they start at the yard, it starts after load-out. Either way, the first arrival should be timed from that place at that hour. That one change often does more for on-time arrival than anything later in the day.
4. Plan for the bad day, not the average day
The FHWA also publishes a Planning Time Index: "The ratio of the 95th percentile travel time to the free-flow travel time." That is the drive on one of the worst days of the month. You don't plan every drive at the 95th percentile, or the board would be empty. But the gap between the average and the bad day is a good guide to how much buffer time a peak-hour drive needs, and to how wide a late-afternoon window should be.
What a schedule needs to get this right
To handle traffic properly, a scheduling system needs three things at the moment it offers a time:
- Where the truck will be, meaning the previous job on that tech's day, not the shop.
- When the drive happens, because 7:15 and 1:15 are not the same drive.
- The drive itself, checked before the slot is offered, not fixed later when the day is already promised.
That is what travel time scheduling means. CrewLink offers only start times a qualified tech can actually make, counting the drive at that hour from the previous job. A real-road travel model for the US, calibrated with live traffic samples, is in build, alongside a plan-vs-actual ledger that records each day's planned drive times against what happened. Until you have that kind of record, your own completed jobs are the best source: compare planned and actual drive time by hour of day and you will see your own peaks.
What to take away
- A drive time is only true for the hour it was measured. Peak drive ≈ free-flow drive × Travel Time Index.
- The FHWA treats 6 to 9 a.m. and 4 to 7 p.m. on weekdays as peak periods. Those are where your first and last jobs sit.
- Keep long hops in the middle of the day and keep peak-hour jobs close together.
- Time the first drive from where the truck really starts, at the hour it really starts.
- Use the gap between an average and a bad drive to size buffers and late-day windows.
Common questions
How much longer do drives take during rush hour?
It depends on your metro and the route. The FHWA's Travel Time Index expresses it as a ratio of peak travel time to free-flow time; an index of 1.3 means 30% longer. Compare your own planned and actual drive times by hour to find your number.
When is rush hour for field service scheduling?
The FHWA's congestion reports use 6 a.m. to 9 a.m. and 4 p.m. to 7 p.m. on weekdays as peak periods, as of October 2026. Local peaks vary, so check your own completed jobs.
Should technicians start earlier to beat traffic?
Sometimes. An earlier start can put the first drive ahead of the peak, but only if customers will accept the earlier arrival. Often the bigger gain is timing the first drive correctly and keeping the first few jobs close together.
How do I account for traffic when booking appointments?
Check the drive from the tech's previous job at the hour the drive would happen, before you offer the time. A slot that works at midday may not work at 4:30.