It's not identical but it has mostly the same risks. Over-consumption paired with complex tasks and/or judgement etc. I expect MJ is less risky, since there's no culture of "smoke it until you literally pass out" like there is with alcohol.
It's certainly less risky to people around you. Google drunk drivers vs stoned drivers.
It's clear marijuana use negatively affects one's ability to drive, making a person twice as likely to get in an accident. However, the odds are demonstrably worse when drinking and driving. An analysis of federal crash data finds that drivers who are young (20-something) and at the legal limit for driving (blood alcohol content of .08 percent), are 20 times more likely to get into a deadly accident than their sober peers.
...
The difference in outcomes for stoned drivers versus drunk drivers lies in the way stoned drivers act behind the wheel. While drunk drivers tend to speed and make risky decisions, stoned drivers lollygag along and play it safe. They're more likely to be stopped for driving far below the speed limit than for surpassing it. Plus, marijuana enthusiasts often toke at home, which lessens the odds of them driving around stoned in the first place
So, marijuana does make you more accident-prone, because stoned drivers are
too timid and drive too slowly. So, they cause a different type of accident to drunk drivers, who tend to speed. Plus, marijuana makes you less likely to want to go out for a drive in the first place. The rise of a marijuana culture would likely massively reduce fatal car accidents. (Offset by a rise in the number of pizza-delivery related incidents).
Don't get me started on beer+grass. That combo will basically glue anyone to their chair. Drunk person causing trouble? Some weed will likely shut them down completely. There are old rhymes such as "beer then grass, you're on your ass, grass then beer, you're in the clear". e.g. if you're stoned then go out for beers you tend to drink slower, whereas if you're drunk then smoke cones it hits you all at once.