Making decisions about where investment should be spent to help achieve policy goals, and providing guidance on when road schemes are appropriate or not, is a very challenging task.
Mae penderfynu ble i fuddsoddi er mwyn helpu i gyflawni nodau polisi, a darparu arweiniad ynghylch yr adegau pan fydd cynlluniau ffyrdd yn briodol neu beidio, yn dasg heriol iawn.