そんな運転をしていたら、事故を起こしかねないよ。
Q. What does 起こしかねない warn about?
Translation
If you drive like that, you could well cause an accident.
Explanation
〜かねない means 'quite capable of (something undesirable) happening'. Learners often misread it as negative because of ない, but it asserts the risk — the opposite of 〜かねる ('cannot').