A.T. Robertson Commentary Luke 19:36

"And as he went, they spread their garments in the way." — Luke 19:36 (ASV)

They spread (υπεστρωννυον). Imperfect active describing the continued spreading as they went on. Hυποστρωννυω is a late form of the old verb υποστορεννυμ. Here only in the N.T.