[Tagging] Access restrictions and expressway=yes

[Fernando Trebien]

On Sat, Feb 20, 2021 at 6:41 PM Minh Nguyen
<minh at nguyen.cincinnati.oh.us> wrote:
>  From a traffic engineering standpoint, an expressway differs from a
> surface street by meeting most of these criteria:
>
> * Designed for high speeds (doesn't necessarily have a high speed limit)
> * A dual carriageway
> * Frontage roads consolidate driveway access
> * A mix of ramps and at-grade intersections

Thank you for the explanation. Our dual carriageways would meet most
of these criteria, most of the time not having frontage roads due to
uncontrolled urbanization. Despite this, building frontage roads is a
long-term development goal for most of them.

> By contrast, motorroad=* apparently is all about access restrictions and
> legal distinctions. [4][5] If expressway=* gets deprecated in favor of
> motorroad=*, then the latter key's definition becomes even more muddled,
> and it becomes even less likely that a global router would ever use it
> for anything.

In fact. If structure were really that important for routing, systems
like OSRM and GraphHopper would prefer dual carriageways with many
lanes, but they don't. Mobility is mainly related to the speed limit
outside cities and traffic patterns inside cities. I was thinking
about the possibility that some would be interested in making their
own cartographic styles from this data.

-- 
Fernando Trebien