Perhap seeing the traffic accident would cause the death of another, but by reading the rules (as I just found, but I'm unsure about the reliability of it) the cause of death may not be related to an event, unless specifically described so. Were Light more patient with the power, perhaps we would see further exploration into the Death Note.
But then I think, the suspense of the series would be cut dramatically or the series would collaspe, were this power discovered. For the sake of the continuity, the creators chose not to show this (possible) aspect of the book, and focused on Light's lunacy and mind battles rather than his ability. Some of the rules are interesting however, and maybe more time could have been spent exploring those secondary rules.
[a href="http://annex.wikia.com/wiki/Rules_of_the_Death_Note"]Rules of the Death Note[/a]
But then I think, the suspense of the series would be cut dramatically or the series would collaspe, were this power discovered. For the sake of the continuity, the creators chose not to show this (possible) aspect of the book, and focused on Light's lunacy and mind battles rather than his ability. Some of the rules are interesting however, and maybe more time could have been spent exploring those secondary rules.
[a href="http://annex.wikia.com/wiki/Rules_of_the_Death_Note"]Rules of the Death Note[/a]