In summary, there are just over 2 incidents a month that cause more than 15 minutes delay, and 5% of these are caused by collisions, and very few by congestion.
Roedd ychydig dros 15,500 o lwybrau’n aros mwy na dwy flynedd, sef y ffigur isaf ers mis Mehefin 2021, dros dri chwarter (78.0%) yn is na’r ffigur uchaf, a gostyngiad o 26.5% ar y mis blaenorol.