This one’s a real head-scratcher.

A car pulls up next to a semi at a light. The semi turns, while the car stays in place; then, predictably, the semi smashes into the car, totaling it almost instantly.

It’s a difficult wreck to watch, and it’s also prompting a ton of arguments online. The issue at hand: Whose fault is the accident?

At first glance, it’s clearly the truck driver’s fault.

After all, he’s the only one moving when the accident occurs. An experienced semi driver should know to check his blind spots in situations like these. A closer look at the situation, however, reveals a few wrinkles.

For one, this accident occurs where a road intersects a one-way road. That means that both vehicles were turning left—there was no other option. Therefore, the driver of the blue car should have been aware of the danger and left more room for the truck.

Adding to the confusion is the video’s country of origin. All of this occurred in the United Kingdom, so U.S. laws are moot. Still, from a common sense perspective, both drivers share a bit of the blame.

YouTube users quickly piled on with their explanations.

“The lorry drove into a stationary vehicle because he only looked to his right and not both ways,” one wrote. “The blue car was ahead of the lorry before the collision happened so the lorry driver was at fault through lack of effective observation, any experienced driver of a large vehicle would anticipate something would likely go into a gap on the left/near side and be prepared for it. Corrective observational training needed for this lorry driver.”

“Footage shows that the lorry could only turn left due to the barriers, therefore the car driver should be aware of that fact and not undertake,” wrote a user on the Daily Mail’s website. “However, look both ways when moving..A lesson has been learnt by both. Had the lorry driver looked right, he would of seen the car, regardless of whether it had the right to be there. Everyone who has passed their driving test knows that lorries swing out to the right when turning left.”

This seemed to be a big point of contention among commenters.

However, this comment provides a decent rebuttal:

“It is an excellent point that you expose, However, it is still his fault. ‘BEFORE YOU ADVANCE YOU MUST LOOK.’ If the traffic regulations say: ‘You are not guilty of accidents if the other car was in your blind spot,’ then if you are right.”

“Truck driver should be blamed. There are 2 turn lines to the left, he cut the line, the blue Toyota Yaris didn’t do anything wrong,” wrote another.

In some cases, the conversation became quite heated, and because this is the internet, people chimed in with various insults and false facts. However, there were a few useful posts; one user noted that the case has been to court. The verdict: The driver of the blue vehicle was found to be at fault.

Check out the video below to see for yourself.