渡る and 渡す: crossing a street and handing something over
Read を with both a crossing route and an object handed over, distinguishing a recipient from a destination.
Cross a street or bridge
信号が青になってから、道路を渡りました。 says that someone crossed the road after the light turned green. With 渡る, read わたる, 道路を is the route crossed.
橋を渡って、向こう岸へ行きます。 means crossing the bridge to the opposite bank. 橋を marks the route, while 向こう岸へ marks the destination.
Hand an object to someone
受付の人に申込書を渡しました。 means that someone handed an application form to the receptionist. With 渡す, read わたす, に marks the recipient and を the item.
この鍵を管理人に渡してください。 asks someone to hand this key to the caretaker. 管理人 is the recipient, not the person doing the handing over.
Check the object despite similar forms
渡る becomes 渡って, while 渡す becomes 渡して. 道路を渡して does not express a person crossing the street, so select the verb as well as the particle correctly.
渡しただけで、相手が読んだかは分かりません。 says that the item was handed over, but it is unknown whether the recipient read it. Handing over does not establish reading or approval.
Does を have the same role in 道路を渡る and 申込書を渡す?
Show the answer and why
It marks a crossing route in the first and an object handed over in the second. The shared particle does not make the structures identical.