Musannaf Ibn Abi Shayba 3:5369

Yazid ibn Harun narrated to us, he said: Hisham informed us, from al-Hasan, from Jabir, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Do not pray on the main roads, and do not camp on them, for they are the dwelling places of snakes and beasts of prey."