Why narrow streets?
We mean very narrow streets that are drive-able, but hard to access by car. It's the kind of roads that are so narrow, you'd rather not get a route through when driving, unless it is significantly faster. However, as a motorcycle, narrow streets are convenient for navigation. We'd expect to find relatively low segment speeds on narrow streets already, due to the physical characteristics of the street.

How does it work in routing?
* Narrow Streets have a penalty for private cars and taxis. The exact value for the penalty hasn't been finalized yet, we're going to run some tests to determine this. The value will likely range between 5-10 minutes. There will not be a penalty for motorcycles.
* We defined the default driving speed on narrow street segments with 10 km/h until speed data is collected after the production release in routing server.

What about navigation that ends on an narrow street?
We navigate to destinations set on an narrow street. House numbers are not supported yet.

Will there be a setting to opt-in/opt-out of narrow street navigation?
No. This is why it's important to only map segments that are drivable, yet inconvenient, for cars.

Anything else that is different?
Routing override (unfavored/neutral/preferred) is not supported in this version.

Renaming of road type
After reading your feedback we hear your concern that the naming (previously: alley) can be confusing to editors in many countries. So we changed the string to “Narrow Street”. In addition you can use transifex to translate the road type and localize it to your context.

Removing the road type from the editor until it goes to production in routing
Unfortunately we cannot simply remove a road type from production editor. As narrow streets were mapped already, removing the road type now can cause issues with editing the affected segments. We are looking into an option to remove the road type, but it’s not something we can do very fast, as there are dependencies with what exists on the map today.

Narrow Streets used as detours for traffic jams on main road.
We hear your concerns about this and are going to look at these things closely while collecting data after it is released to routing production.
However, you can use this road type to apply a small penalty on narrow roads that people get detours on frequently today, that you’d like to discourage.

Users should be able to configure their preference in driving on Narrow Streets
We don’t see this as option that would benefit the majority of users. From our experience, we know that often these settings can cause misunderstandings that could lead to problematic routes for a user.

Will going from 1 Narrow Street segment to the next have any additional penalty, or is it just when leaving the road type? Will the penalty stack, so if the route crosses a Narrow Street then a street then an Narrow Street then a street, is that 1 instance of a penalty or 2?
* For continuous Narrow Street segments, the penalty will not be multiplied. (i.e.: 4 continuous Narrow Street segments will have the same penalty as one Narrow Street segment).
* Non-continous segments the penalty will be applied to each Narrow Street section. (i.e.: 4 continuous Narrow Street segment (+one time penalty) > other street segment > Narrow Street (+one time penalty).

This should have been implemented like a segment attribute (like tunnel) instead of a specific road type.
We don’t currently see the benefit of adding this as an attribute to higher-level street types, as it will be connected to low default segment speeds.

The color of the Narrow Street & Private Streets are now same (brown). Please change its color.
We’re working with the devs to change this for easier differentiation of the two.

Please let me know if you have any questions. We'll try to keep this opening post updated with an FAQ.

Best,
Daliah

This post was edited and updated to reflect the information provided in staff posts from:
May 1, 2018
May 16, 2018