0.5 of the thin preset is the thinnest that still draws a line inside its outline, 1 px within
2 px at the lowest zoom; 2 of the thick one is a 30 px line at street zooms, about a motorway's
width. Beyond either end the route stops reading as a line over the roads it follows.
The values RoutingModuleConfig.widthFactor and a section's
widthFactorare clamped to.