roads.mss

/* ==================================================================
   ROAD & RAIL LINES
/* ================================================================== */

/* At lower zoomlevels, just show major automobile routes: motorways
and trunks. */

#roads_low[zoom=9] {
  [type='motorway'] { line-color: @motorway_line; }
  [type='trunk'] { line-color: @trunk_line; }
  [zoom=5] {
    [type='motorway'] { line-width: 0.4; }
    [type='trunk'] { line-width: 0.2; } }
  [zoom=6] {
    [type='motorway'] { line-width: 0.5; }
    [type='trunk'] { line-width: 0.25; } }
  [zoom=7] {
    [type='motorway'] { line-width: 0.6; }
    [type='trunk'] { line-width: 0.3; } }
  [zoom=8] {
    [type='motorway'] { line-width: 1; }
    [type='trunk'] { line-width: 0.5; } }
}

/* At mid-level scales start to show primary and secondary routes
as well. */

#roads_med[zoom>=10] {
  [type='motorway'],
  [type='motorway_link'] {
    line-color: @motorway_line;
  }
  [type='trunk'],
  [type='trunk_link'] {
    line-color: @trunk_line;
  }
  [type='primary'] { line-color: @primary_line; }
  [type='secondary'] { line-color: @secondary_line; }
  [type='tertiary'] { line-color: @standard_line; }
  [zoom=9] {
    [type='motorway'],[type='trunk'] { line-width: 1.4; }
    [type='primary'],[type='secondary'],
    [type='motorway_link'],[type='trunk_link'] { line-width: 0.6; }
  }
  [zoom=10] {
    [type='motorway'],[type='trunk'] { line-width: 1.2; }
    [type='primary'],[type='secondary'],
    [type='motorway_link'],[type='trunk_link'] { line-width: 0.6; }
  }
}

/* At higher levels the roads become more complex. We're now showing 
more than just automobile routes - railways, footways, and cycleways
come in as well.

/* Road width variables that are used in road & bridge styles */
@rdz11_maj: 0.8; @rdz11_med: 0.4; @rdz11_min: 0.2;
@rdz12_maj: 1.4; @rdz12_med: 0.8; @rdz12_min: 0.5;
@rdz13_maj: 1.6;   @rdz13_med: 1.0; @rdz13_min: 0.8;
@rdz14_maj: 2;   @rdz14_med: 1.6; @rdz14_min: 1.0;
@rdz15_maj: 3;   @rdz15_med: 2;   @rdz15_min: 1.2;
@rdz16_maj: 8;   @rdz16_med: 6;   @rdz16_min: 4;
@rdz17_maj: 14;  @rdz17_med: 12;  @rdz17_min: 10;
@rdz18_maj: 20;  @rdz18_med: 17;  @rdz18_min: 14;