Al-Husayn ibn Sa‘id, from Hammad, from Hariz, from Muhammad ibn Muslim, who said:
I asked Abu Abdillah عليه السلام, peace be upon him, about prayer during travel. Imam عليه السلام said: "Do not pray on the main road (jadah); rather, move to its sides."
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 2, p. 235