I used the following Overpass files to measure the amount of cycle lanes in cities:
[out:csv(number,length)]; {{geocodeArea:Westminster}}->.searchArea; way["highway"]["highway"!="cycleway"]["highway"!="bridleway"]["highway"!="footway"]["highway"!="path"]["highway"!="service"]["access"!="private"](area.searchArea); make stat number=count(ways),length=sum(length()); out;
[out:csv(number,length)]; {{geocodeArea:Westminster}}->.searchArea; way["highway"="cycleway"]["foot"!="designated"](area.searchArea); make stat number=count(ways),length=sum(length()); out;
[out:csv(number,length)]; {{geocodeArea:London borough of Camden}}->.searchArea; way["highway"="cycleway"](area.searchArea); make stat number=count(ways),length=sum(length()); out;
Click the zoom icon once generated
[out:json]; {{geocodeArea:Westminster}}->.searchArea; ( way["highway"="cycleway"]["foot"!="designated"](area.searchArea); ); out body; >; out skel qt;
[out:json]; {{geocodeArea:Westminster}}->.searchArea; ( way["highway"]["highway"!="cycleway"]["highway"!="bridleway"]["highway"!="footway"]["highway"!="path"]["highway"!="service"]["access"!="private"](area.searchArea); ); out body; >; out skel qt;
[bbox:{{bbox}}]; ( way["highway"="cycleway"]; ); out geom;
[date:"2014-10-27T00:00:00Z"] [out:json][timeout:25]; nwr["amenity"="bank"]({{bbox}}); out geom;
[out:csv(length,value)]; area[name="London"]->.a; way[highway](area.a); for (t["highway"]) { make stat value=_.val,length=sum(length()); out; }
[out:csv(length,value)]; area[name="London"]; way[highway="cycleway"]; out for (t["highway"]) { make stat value=_.val,length=sum(length()); out; }
[out:csv(length,value)]; area[name="Isle of Man"]->.a; way[highway="cycleway"](area.a); for (t["highway"]) { make stat value=_.val,length=sum(length()); out; }
[out:csv(length,value)]; area[name="Isle of Man"]->.a; way[highway="cycleway"](area.a); make stats length=sum(length()); out;
[out:csv(length,value)]; area[name="London"] .way[highway="cycleway"] .way[cycleway="sidewalk"]; make stats length=sum(length()); out;
[out:csv(length,value)]; area[name="London"]; way[highway="cycleway"](area)->.a; way[highway="cycleway"](area)->.b; way.a.b; make stats length=sum(length()); out;
[out:csv(length,value)]; area[name="London"]; way[highway="cycleway"](area)->.a; way[cycleway!="sidewalk"](area)->.b; way[foot!="yes"](area)->.c; way.a.b.c; make stats length=sum(length()); out;