Why are estimated journey times too long?

Help and support
1

I recently started having a go with the Organic Maps app which uses OSM data for maps & routing. I noticed that it estimates journey times much longer than the estimates by Osmand and Google Maps for the exact same road trip.

I then logged into OSM.org to see what it would come up with and I found it also estimates a long journey time (the exact same estimate as Organic Maps, actually).

I found the article How to understand and edit factors contributing to drive time - Help and support - OpenStreetMap Community Forum but TBH I don’t understand how to turn that into a solution. I’m wondering if the travel time difference may be a result of confusion over kms or miles, but I can’t find any account preferences that would set that in OSM.org.

Could it be that the car.lua file mentioned in that article has a speeds section in mph not kmh which could account for the unusually high travel time estimates? And if so, what can be done about that?

speeds = Sequence {
  highway = {
    motorway        = 90,
    motorway_link   = 45,
    trunk           = 85,
    trunk_link      = 40,
    primary         = 65,
    primary_link    = 30,
    secondary       = 55,
    secondary_link  = 25,
    tertiary        = 40,
    tertiary_link   = 20,
    unclassified    = 25,
    residential     = 25,
    living_street   = 10,
    service         = 15
  }
},
2

linked things is about OSRM and you report problems with Organic Maps

these software use different time estimates

report it back to Organic Maps (and/or Comaps fork)

if there is existing issue: comment there

likely with an exact to/from and what would proper estimate would be

also, you can post to/from points here -maybe OpenStreetMap misses surface/maxspeed info? Or some roads/paths are missing so it suggest wrong, too long route?

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3

I think the root of the issue is with OSRM. Organic Maps and OSM are probably both using OSRM for routing. I didn’t realise until now that OSM uses OSRM (a different set of software) for its routing.

I think Osmand uses other routing algorithms as well as OSRM and that could explain why its journey times are different.

I had a look at some OSRM posts and it looks like this issue was identified at least 6 years ago.

4

The OSM website offers three routers (OSRM, Graphhopper, Valhalla). All of these are independent of OSM itself. It might be worth checking all three to help confirm if this is specific to OSRM.

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6

This is how it looks on mobile. The drop down at the top where it says “Graphhopper” allow selecting among the 3 options.

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7

I’m pretty sure Organic Maps has its own custom routing algorithm.

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8

Thanks. It’s clear that the OSRM routing API is the issue.

OSRM: Distance: 86km. Time: 3:24.
GraphHopper: Distance: 86km. Time: 1:38.
Valhalla: Distance: 86km. Time: 2:01.

9

Have you looked at the network traffic from Organic Maps to see if it’s calling the same OSRM server as osm.org? Because if not, then it’s not “clear” at all.

tbh, car journey time estimates in most parts of the world are dependent on traffic levels, and so any purely OSM-based router is going to struggle with finding anything realistic.

10

This is a good indication that there’s something in the data that osrm is interpreting differently than the other two. The 20 minute difference between GraphHopper and Valhalla indicates that as well (in straightforward routing scenarios the estimates are usually much closer). That something in the data could also be influencing Organics Maps estimates.

If you don’t tell us the route you’re planning with starting and stopping points, it’s really hard to guess why the estimates are different. Is there a ferry? Or an unpaved road through highlands? We really can’t say.

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11

I’m not so sure, I see big differences even on straightforward routes along main roads, at least in Spain. I have the impression that OSRM gives consistently much higher estimates than the other two where routes are mainly on motorways, but results are more scattered on other road types, even primary.

It’s certainly not a scientific test but seems to suggest significant differences in assumed speeds (with whatever profiles are used in this context), even without exotic complications like ferries or unpaved roads.

In any case as you say, without examples we can’t know if it is just a general difference in defaults or something more specific.

12

I can provide the start and end points of the route here. It’s in Western Australia. I’ll provide the exact GPS coordinates as well as screenshots as hopefully that’s useful to everyone.

Start: Manning Gorge Campground
16.65743° S, 125.92765° E

Screenshot_2025-06-26-19-56-50-26_014aeb6b5e04ee7837dcdaecc5244511
Screenshot_2025-06-26-19-56-50-26_014aeb6b5e04ee7837dcdaecc52445111080×2400 231 KB

End: Imintji Campground
17.14971° S, 125.45671° E

Screenshot_2025-06-26-20-00-48-29_014aeb6b5e04ee7837dcdaecc5244511
Screenshot_2025-06-26-20-00-48-29_014aeb6b5e04ee7837dcdaecc52445111080×2400 210 KB

FYI the road is mostly an unsealed road but traffic would be moving typically at around 70-80kph in my estimation.

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I guess OSRM assumes a maximum of 40 km/h for surface=unpaved roads.

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15

Yes that must be it.

16

Reading your comment about 70-80 kph my western European mind was thinking that’s totally crazy, unless you are driving a rally car.

17

Seemed a bit high to me too, based on having been on some unsealed WA roads as a tourist!** I suspect practical maximum speed would be hugely variable depending on the state of the road (not just potholes, washboarding etc.).

** but clearly the locals know more than me…

18

From my own experience I can tell you that 100kmh can be done relatively easily on some American dirt roads when they are straight and in good condition.
But that’s mostly the speed locals will go.
I’ve seen lots of roads being limited to 35 mph (55km/h) because higher speeds lead to more wash-boarding.

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19

Outback unsealed roads have good sections and bad sections. Some might be good for only 30-40 kmh while other sections are actually quite good and you can drive at 70-80 kmh, or higher.

20

Locally here where I am at (Michigan, US) about half of our road miles are unsealed. Or in other words dirt/gravel mix. They do maintain them quite well & 50-60 mph (80-97 km/h) is not a problem.

21

To address the issue of journey time estimates, perhaps consider tagging the surface as compacted rather than unpaved, if this is accurate for the roads in question.

“Unpaved” could be anything, potentially with deep ruts barely suitable for anything other than a tractor. A well maintained compacted road, although not sealed, allows travel at speed. You also see this in the OSRM presets linked by fschmidt.

edit: a smoothness=* tag could in turn help to indicate how well-maintained the road is

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