GTrafficOverlay
Right now it only works in the United States, but just by activating enableGTrafficOverlay you can access the traffic information.
Code.aspx
<cc1:GMap ID="GMap1" runat="server" />
Code.aspx.cs
GMap1.setCenter(new GLatLng(42,-95), 3);
GMap1.enableGTrafficOverlay = true;