# Isochrones - Travel speeds / Routing algorithm **URL:** \ **Category:** isochrones\ **Created:** [July 8, 2022, 12:34pm UTC](https://ask.openrouteservice.org/t/isochrones-travel-speeds-routing-algorithm/4018 "2022-07-08T12:34:29Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Petar\_Koljensic](https://ask.openrouteservice.org/user_avatar/ask.openrouteservice.org/petar_koljensic/32/1748_2.png) [@Petar\_Koljensic](https://ask.openrouteservice.org/u/Petar_Koljensic)\ **Post date:** [July 8, 2022, 12:34pm UTC](https://ask.openrouteservice.org/t/isochrones-travel-speeds-routing-algorithm/4018/1 "2022-07-08T12:34:29Z")
Hi all, I am working on a project about 15-Minute-Cities, where I am calculating 15 minute isochrones from various amenities in urban context. Therfore I am using different modes of transport. What are the speeds for each of modes in the isochrones modul? Are there some impacts (e.g. elevation, surface, etc.) on the speed by calculation of isochrones? Thanks! Petar ---
**Author:** ![amandus](https://ask.openrouteservice.org/user_avatar/ask.openrouteservice.org/amandus/32/669_2.png) [@amandus](https://ask.openrouteservice.org/u/amandus)\ **Post date:** [July 11, 2022, 7:46am UTC](https://ask.openrouteservice.org/t/isochrones-travel-speeds-routing-algorithm/4018/2 "2022-07-11T07:46:01Z")
Hi @Petar_Koljensic, > **[Travel Speeds | openrouteservice backend documentation](https://giscience.github.io/openrouteservice/technical-details/travel-speeds/)** > > openrouteservice backend documentation Best regards ---
**Author:** ![Petar\_Koljensic](https://ask.openrouteservice.org/user_avatar/ask.openrouteservice.org/petar_koljensic/32/1748_2.png) [@Petar\_Koljensic](https://ask.openrouteservice.org/u/Petar_Koljensic)\ **Post date:** [July 14, 2022, 5:04pm UTC](https://ask.openrouteservice.org/t/isochrones-travel-speeds-routing-algorithm/4018/3 "2022-07-14T17:04:06Z")
Thanks! I found it in the meantime.