<div dir="ltr"><span class="gmail-im"><div dir="ltr">On Thu, May 6, 2021 at 4:49 PM Roff, Thomas (FHWA) <<a href="mailto:Thomas.Roff@dot.gov" target="_blank">Thomas.Roff@dot.gov</a>> wrote:<br></div></span><div class="gmail_quote"><span class="gmail-im"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">





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<b><span style="font-size:9.5pt;font-family:"Arial",sans-serif;color:black">1</span></b></p>
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<span style="font-size:9.5pt;font-family:"Arial",sans-serif;color:black">Full Access Control</span></p>
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<span style="font-size:9.5pt;font-family:"Arial",sans-serif;color:black">Preference
 given to through traffic movements by providing interchanges with 
selected public roads, and by prohibiting crossing at-grade and direct 
driveway connections (i.e., limited
 access to the facility).</span></p>
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<span style="font-size:9.5pt;font-family:"Arial",sans-serif;color:black">Partial Access Control</span></p>
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<span style="font-size:9.5pt;font-family:"Arial",sans-serif;color:black">Preference
 given to through traffic movement. In addition to interchanges, there 
may be some crossings at-grade with public roads, but, direct private 
driveway connections have been minimized
 through the use of frontage roads or other local access restrictions. 
Control of curb cuts is not access control.</span></p>
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<span style="font-size:9.5pt;font-family:"Arial",sans-serif;color:black">No Access Control</span></p>
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<span style="font-size:9.5pt;font-family:"Arial",sans-serif;color:black">No degree of access control exists (i.e., full access to the facility is permitted).</span></p></td></tr></tbody></table></div></div></blockquote><div><br></div></span><div>Thank you, Thomas.  This is the clearest distinction I've seen yet.  <br></div><div><br></div><div>It
 seems to me that with regard to freeways, expressways, parkways, 
motorways, super twos (and other names) people seem to care about 
distinguishing two main things:  1) divided or not, 2) degree of access 
control.  Looking at TagInfo I see there are tags with some usage for 
each of these things and I'd suggest we start using them more heavily:<br><br><a href="https://taginfo.openstreetmap.org/keys/dual_carriageway" target="_blank">https://taginfo.openstreetmap.org/keys/dual_carriageway</a></div><div><a href="https://taginfo.openstreetmap.org/keys/access_control" target="_blank">https://taginfo.openstreetmap.org/keys/access_control</a></div><div><br></div><div>So
 highway=motorway implies dual_carriageway=yes and access_control=full. 
 Lower classes of highway= can have access_control=full|partial|none
 and dual_carriageway=yes|no.  Tagging dual carriageway explicitly feels
 a bit redundant since we draw two ways, but it would allow a rendering 
variation and probably make some other things easier for data consumers.</div></div></div>