I have seen it said by many elsewhere on the net that Zodiac planned his crimes in advance with meticulous detail and was an organized killer. Faff I say, lol.

Zodiac, from the evidence as we know it, seems to have been a opportunistic killer in all bar one of his attacks. How could Zodiac ‘Plan’ to murder anyone on that Island at Berryessa, when Bryan and Cecilia didn’t decide to go there untill ‘The last minute?’ Same for LHR & BRS. Zodiac seems to have driven around hunting or victims with no apparant ‘Plan’ to attack a couple at a certain location or time, but rather attack a couple who he found/stumbled across who were in the wrong place at the wrong time. This method of killing is risky.
If you want an example of an organized, methodical planning serial killer, then BTK – Dennis Raider, is a perfect example. He prowled the streets looking for a victim and would settle on a specific woman who, if she wasn’t home when he spotted her, would follow her home so he knew where she lived. He’d then watch his victims for months, geting to know her routine, and planning his attack which would usually involve cutting the phone line, breaking into her home while she is out, and waiting for her to return before ambushing her in her home.

I believe Zodiac’s final choice of victim may have been as a result of his previous attacks being attacks of opportunity, where the victim’s decide the location of the attack. Let’s not forget that the attack that preceded the Presidio Height’s attack, was Lake Berryessa. At Lake B on the day of the attack, several witnesses subsequently came foreward to say that they had witnessed a strange lone male lurking around the lake area that day, and if this was Zodiac, then this again suggests the opportunistic nature of his crimes as he’s clearly loitering waiting for an opportunity/victim to present itself. This again, is risky, time consuming, and has no guarntee of being successful.

It’s likely that he had had enough of relying on victims to come to him, searching for them, and allowing them to dictate the time and precise location the crime will take place, and so probably asked himself how he could get a victim to come to him, and at a certain place of his choice, and at the time he decided. Who will always come to you when you want them, and go where you instruct them? Taxi Drivers.

If this theory is correct, then it’s utterly ironic that this change of MO adopted by Zodiac in order for himself to control the where, the when, the how, and the escape, is the very attack that almost, and certainlly should have, led to his arrest & capture.