the weather in rio de janeiro can be highly unpredictable and create unsafe road conditions - this being said, always check forecasts and take a look outside before driving. avoid driving in heavy rain if possible, taking a pause in a safe location until the weather clears up - police checkpoints and roadblocks are somewhat common but can be handled with ease following a few simple steps.

when approaching a roadblock, slow down, open all windows and turn on all interior lights so police can see the driver and passengers - have the aforementioned documents on hand and ready to be presented when they are asked for. 

as is the case in most countries around the world, drinking and driving is a criminal offense in brazil and is treated seriously - never drink and get behind the wheel or have open containers of alcohol in a car, whether moving or stationary.