Someone is always at fault. Accidents aren't really "accidents" they're collisions, and they don't just happen. Someone will be blamed, and sometimes there's more than enough blame to go around.
- Related Read: Accident Prone: When Car Accidents Happen
Ontario's at fault rules (officially called Fault Determination Rules) detail more than 40 different collision scenarios to help ensure that all drivers are treated the same.
- Related Read: Traffic Tickets, Fender-Benders And Your Insurance
Common At Fault Accidents
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Getting Rear Ended
- You're motoring along and traffic ahead of you slows down. You slow down as well. Then, BAM! The driver behind you rear ends your car. It's only you and the other driver involved.
Who is at fault?
The driver who rear ended your car is 100% at fault for the collision. 
You're driving along and come upon a red light. There's already a car stopped ahead of you in the lane. You stop, no problem, but the driver behind you doesn't. CRUNCH! Just your luck! You've been rear ended, which then causes you to rear end the car in front.
Who is at fault?
The driver who rear ended your car is 100% at fault for the collision. For both you and the driver you ended up rear ending, it's a not at fault accident.- Your GPS tells you that you've got to take the next left. You signal and begin to slow down. There's a car coming in the opposite direction; you can probably make the turn but it looks like she's coming on fast so you decide to wait-better safe than sorry, right? Suddenly, CRRRACK! Clearly the driver behind you thought you were going to make the turn too and he rear ends you.
Who is at fault?
The driver who rear ended your car is 100% at fault for the collision. 
You're cruising along and the car ahead of you is driving a tad slow for your liking, but you haven't had an opportunity to pass him just yet. Suddenly, the car behind you rear ends you, driving you right into the car ahead of you too.
Who is at fault?
Well, the driver who rear ended you is 100% at fault for rear ending you; however, you're 50% at fault for rear ending the car in front. The only driver who is not at fault, is the lead driver. Sure, the accident only happened because you were rear ended, but you likely weren't keeping a safe distance back. Otherwise, you wouldn't have rear ended the car in front.
U-Turn Accidents- That darn GPS! Your GPS has steered you in the wrong direction (again). You should have turned left five streets back. You decide to do a U-turn; there's no one coming in the opposite direction, and there's no one in your rear view mirror. As you swing around though, a car from a side street approaches and doesn't realize you're doing a U-turn and you don't see them either. WHAMMM! You hit the car.
Who is at fault?
You are 100% at fault for the collision. Anyone doing a U-turn which ends up in a collision is 100% at fault.
Car Pile-Ups 
You're motoring along the highway (doing the speed limit, of course) when out of nowhere-it seems-you see everyone frantically hitting their brakes; there's screeching and the sound of metal on metal. It happens so fast, you don't have time to react and next thing you know you're in a 10 car pile-up.
Who is at fault?
Regardless of whether you hit one car in the pile-up or three cars, every driver involved in the collision will be considered to be 50% at fault.
Pulling Out Onto A Street From A Driveway- You're driving along, minding your own business when SLAM! A car, coming out of someone's driveway, clips the back corner of your car. There is no reason why you needed to stop and let them in; there's no stop sign or light.
Who is at fault?
The driver who clipped you is 100% at fault for the collision.
Sideswipes 
Admittedly, you like to hug the line while driving. But apparently, so does the driver on the other side of the road. Suddenly, BANG! You're car has been sideswiped (or perhaps, you've just sideswiped the other driver's car). Regardless, you've both just lost your side view mirrors.
Who is at fault?
You'll both be attributed 50% fault for the collision since you were both hugging (but not over) the centre line.
Doors Left Ajar- While driving you suddenly are overcome with a wave a nausea. You pull over to the shoulder of the road, and get out just in time to avoid making a mess in your car. Unfortunately, in your haste you've left your car door wide open and a car hits your car door taking it off its hinges.
Who is at fault?
You are 100% at fault for the collision. Anyone who leaves a car door open that then results in a collision is 100% at fault.
Backing Up - You're backing up out of your driveway, when another car coming down the street basically rear ends you. They rear ended you, so they're at fault, right? Wrong.
Who is at fault? You are 100% at fault. Basically anyone who while backing up their car ends up in a collision is deemed to be wholly at fault. (This is true in parking lots too.)
At fault accidents typically will affect your car insurance premiums. And, while obviously it is safety that is most important, there are also financial benefits for being alert, aware and careful while behind the wheel. By focusing on your driving and keeping your record clean, you have a better chance of keeping a low car insurance premium-which can be tough to do if you are in an at-fault collision.
