I have to use Openstreetmap Valhalla. Why slower on rute?

Nicoline_Mølsted · 2024-08-29T19:15:13.884Z

Hi
I have to use a second provider to get benefits for driving to and from my College. They are using openstreetmap and the “valhalla”-type. But the time said on the Valhalla type is off from what is actually the time.
I drive between Hjallesevej 102, Odense M Denmark and Degnevej 16, Esbjerg Ø. I stay at the speedlimet or 10-20 km/h lower, but the time on Valhalla is stil much greater than what it takes to drive. It takes approximately 1 hour and 23/24 minuts with my driving style as explained, but Valhalla says 1 hour and 33/34 minuts.
Why is there such a diffrence?

I have driving on that rute numerous times, and is it only longer in bussystem hours, and then it is like 1 hour and 33 minuts.

Help?

Jochen_Topf · 2024-08-30T04:43:10.151Z

So there is a difference of about 10% in the time estimation? I would think this is actually rather good! Time estimation is done by looking at maximum speed, type of road, number of traffic lights etc. There will always be an error. This is still just an estimate and it will vary by time of day, road conditions etc. That’s totally normal.

Google is able to do better predictions because there are millions of phones out there travelling on every road there is. And Google is tracking all of them in real time and keeping that information, probably for ever, to improve their predictions. Frankly, I’d rather have somewhat less accurate predictions…

Kovoschiz · 2024-08-30T09:47:18.100Z

Unrelated but for reference and interest, TfL uses ±10% at 95% confidence interval for journey time data collection in travel surveys for traffic simulation, same as TAG (DfT)

https://content.tfl.gov.uk/traffic-modelling-guidelines.pdf#page=121 (s2.3.4.3)
https://assets.publishing.service.gov.uk/media/664db4debd01f5ed32793ffc/tag-m1-2-data-sources-and-surveys.pdf#page=43 (s4.3.23)

There’s even a mention of OSM for using Openrouteservice https://assets.publishing.service.gov.uk/media/664db4debd01f5ed32793ffc/tag-m1-2-data-sources-and-surveys.pdf#page=20 (s3.4.13)
The model is validated at the higher of 15% or 1min for 85% of routes https://assets.publishing.service.gov.uk/media/664dad464f29e1d07fadcc39/tag-m3-1-highway-assignment-modelling.pdf#page=33 (s3.3.15)