Driving Durations are off

[masterpoi]

We have noticed that there are often large discrepancies in the driving times when compared to for instance Google Maps / Bing Maps.
For instance, driving this part of the Trans-Canadian highway:

https://www.google.com/maps/dir/52.8683972,-118.0816962/52.9762822,-119.4175245/@52.9342288,-118.8057009,10z/data=!4m2!4m1!3e0
Takes 1h 4m.

http://map.project-osrm.org/?z=15&center=52.987756%2C-119.397440&loc=52.868845%2C-118.078823&loc=52.977124%2C-119.417267&hl=en&alt=0
1h 12m.

https://api.mapbox.com/directions/v5/mapbox/driving/-118.076973%2C52.869235%3B-119.413579%2C52.976750.json
6655.2 seconds or 1h 51m! Which averages to 56km/h.

What is causing this difference? Is there something we can do to get more accurate numbers?

P.s. I'm not sure if this is the right place for this kind of issue, if not, can someone please point me in the right direction?