The car icons are not very visible both on the day and the night maps. It would be helpfull if I would be able to select two icons: for day/night maps
Another work around would be a white silhouette around the icon, so that a blue icon will be more visible over a a blue route, and a red one will be visible on a traffixc jam.
A Zebra icon (like a British police car) can also be visible - yet less populare...