<renderingAttribute name="route">
<!-- fluorescent: filter attrColorValue="#CCFF6600"/ -->
<!-- was badly visible on motorways: filter nightMode="false" attrColorValue="#960000FF"/ -->
<!-- color used for route line color -->
<!-- color_0 used for route line stroke color -->
<!-- color_2 used for route direction arrows -->
<!-- color_3 used for turn arrows on the route -->
<case color="#882a4bd1" strokeWidth="12:8" color_3="#ffde5b" color_2="#bfccff" strokeWidth_3="5:7">
<apply_if nightMode="true" color="#ffdf3d" color_2="#806f1f" color_3="#41a6d9" strokeWidth="9:8" color_0="#CCb29c2b" strokeWidth_0="12:8"/>
</case>
</renderingAttribute>
try strokeWidth_3 for arrow width