Have to agree with all the others, most likely oil. Good that it cleared out, but if you find yourself in situation like this, change the oil and filter at first opportunity. Good synthetic will be less prone to thermo breakdown but even if you stick with the dino, for most parts it will meet most situation.
If you find yourself stuck in traffic or a shut down, best thing to do is get over to the shoulder or a parking lot and shut her down and let it cool while you have a smoke or cold one. Also if it is something you can not avoid, try to find a side road that is less back-up to get the air flowing across so you can get it cooled down occasionally.
These V-Twins can take a hell of allot of abuse and high temps. Hell they ride them in Dubai and Kuwait and those temp can get ridiculus. Oil cooler may helop due to extra oil capacity and ability to drop temp more when air is flowing, not a whole lot of help when stuck other than may take longer to get the oil hot since there is more of it.
