The language used, that 'the victim possibly picked up another fare (suspect) en route to his original assignment' seems to suggest that the exact location of Zodiac entering the taxicab has not been pinned down, despite the charter indicating the origin of the fare be noted. Investigators took a reading of the taxicab meter at 10.46 pm and calculated the Zodiac likely entered the taxicab somewhere in or close to Union Square.
The journey time from Union Square, traveling through in excess of thirty intersections to Washington and Cherry Street, is approximated on Google maps as 12 minutes. However, the taxicab, on a busy Saturday night, would have arrived in 9-10 minutes had Leroy Sweet's 9.45 pm statement been accurate. Leroy Sweet directed Paul Stine to a fare on 500 9th Avenue, and the assumption was, that somewhere en route the Zodiac Killer flagged down the taxicab.
It seems unlikely that Paul Stine would stop for a random customer on the off chance he was going in roughly the same direction. If you pulled up and the person stated he was going in the opposite direction, do you just simply say sorry, and drive off. It is more likely that your taxicab is stationary when your potential fare approaches, just as your receiving the dispatch from Leroy Sweet to proceed to 500 9th Avenue. Then, upon hearing a destination of Washington and Cherry, it makes perfect sense to accommodate the pedestrian, as you are traveling in that direction anyway. A 9-10 minute journey is possible, but it's a tight timeline.
Then we factor in another statement in the police report: "Victim allegedly never arrived at the above location as the dispatch was reassigned to another cab at 9:58 pm." Even if we take this journey at 10 minutes, Paul Stine has to drop this passenger off, and then proceed to 500 9th Avenue, which is a further journey time of 5 minutes from the Washington and Cherry intersection. Trimming this down to 4 minutes, and allowing for the previous passenger to pay and vacate the vehicle, we have a minimum journey time to 500 9th Avenue from Union Square of 14 minutes, and that is a stretch. From a starting point of 9.45 pm, this should have Paul Stine reaching 500 9th Avenue at 9.59 pm. Yet, reading between the lines, Leroy Sweet is already reassigning this fare to another taxicab at 9.58 pm. How did Leroy Sweet conclude that Paul Stine was somehow late?
If this were the case, and Leroy Sweet knew that Paul Stine was much closer to 500 9th Avenue than Union Square or thereabouts, then it could be argued that he would reallocate the fare to another taxicab, that wouldn't be justified after just 13 minutes (9.58 pm minus 9.45 pm). Even if Leroy Sweet thought that Paul Stine was 5 minutes overdue, then he would have been expecting Paul Stine to reach 500 9th Avenue by 9.53 pm, which is an impossible journey time on Saturday night of 8 minutes from Union Square.
This could indicate that Leroy Sweet knew that Paul Stine was proceeding west, towards Washington and Cherry, when he gave Paul Stine the 9.45 pm dispatch. But even this, hardly explains the impatience of reallocating another taxicab to the aforementioned destination.
The simplest answer could be, that Leroy Sweet dispatched Paul Stine at 9.35 pm, not 9.45 pm. thereby justifying any perceived impatience on his part, however, this turns the journey time of Paul Stine from Union Square to the Washington and Cherry Street intersection, into a 20 minute journey, which is now too long. Unless something happened along the way? Something that takes the focus away from the crime scene.
These are the details regarding the taxicab meter reading taken from a previous post.
The rates of fare for taxicabs and sedans shall be as follows: Fifty-five Cents (55c) for the first one-fifth mile or "flag": Ten Cents (10c) for each additional one-fifth mile or fraction thereof: Ten Cents (10c) for each one and one fourth minutes of waiting or traffic delay time.
'The police report stated that Paul Stine's taxicab meter read $6.25 at exactly 10.46 pm. So using the taxicab meter charges here, we can backtrack and calculate the approximate pick-up point from the last known movements of Paul Stine heading back from San Francisco International Airport.
The time of the murder was specified as 9.55 pm, so by the time the meter was read at 10.46 pm, the meter had been running idle for 51 minutes. We know that it's 10c for each one and one fourth minutes (1.25) of waiting or traffic delay time. So we can discover the charge the idle taxicab ran up for these 51 minutes. (51 divided by 1.25) = 40.8. Multiplied by 10c = 4 dollars and 8 cents. The investigators deducted this from the $6.25 to give us $2.17. This calculation however, did not include any idle time en route from the proposed theater district to the intersection of Washington and Cherry. But we shall assume it negligible, as they have done.
We know it is 55c for the first one-fifth mile. So the taxicab meter would be operating effectively from $2.17 minus 55c thereafter ($2.17 minus 55c) = $1.62. So to calculate the distance traveled we have to use the taxicab meter charges of 10c for each additional one-fifth mile or fraction thereof.
$1.62 divided by 10c = 16.2 miles. But it is for one-fifth of a mile, so 16.2 divided by 5 = 3.24 miles traveling distance. But again, this is not factoring in any delays en route, in accordance with the History Channel calculations.
The crucial part is the 55c for the first one-fifth mile or "flag." The taxicab should be reading 55c after one-fifth of mile (0.2 miles) is achieved. Therefore, this should be added on to the 3.24 miles, to give us 3.44 miles traveling distance. This would, without any delays en route (not factored in by the History Channel), take us a little further away from Washington and Cherry.'
But these calculations are a fragile balance. What if the idle time above was 61 minutes in total, instead of 51 minutes, and Leroy Sweet's 9.45 pm, was in fact 9.35 pm. This makes the journey time from Union Square to Washington and Cherry, 20 minutes. This could be 10 minutes with the taxicab in motion, and 10 minutes parked up anywhere en route.
Below are two parks, the accessibility at night in 1969 I have no idea. These two parks, Lafayette and Alta Plaza, would not take the taxicab off route, and could have been used (holding the taxicab driver under gunpoint) by either entering or parking alongside, to execute Paul Stine. The murderer could take 10 minutes, or anytime up to 10 minutes to shoot the taxicab driver and remove a piece of shirt, before taking control of the vehicle and driving it to Washington and Cherry, accidentally or mistakenly parking the taxicab one block further west to the destination he gave as Washington and Maple- the one recorded on the trip sheet. This could explain the lack of gunshot and the assumed confidence displayed by the killer in removing the shirt piece at the crime scene- because he had already acquired it. He may have began to leave the crime scene, but returned via the front passenger door to recover the keys he had touched, wiped the steering wheel, driver side compartment, before leaving and wiping down both exterior doors. The three teenagers pick up the story once he has entered the front passenger door. This may seem unlikely, but a simpler variation of this is certainly possible.
One has to remember though, that any extra idle time can dramatically affect the potential origin or pick up point of the Zodiac Killer. The taxicab sitting idle for an extra, let's say, 3 minutes somewhere along the route, will have a marked effect.
However, this 2.96 miles, is closer to the 3.00 miles from Mason and Geary to the crime scene, as calculated by Google maps, than the 3.44 miles calculated above. Without knowing the exact 'traffic delay time' experienced during Paul Stine's final journey, we cannot say with any confidence that the taxicab parked up along the route to Washington and Cherry. However, we can say that, if this was the method employed to discover the location of where Zodiac entered the taxicab, it could be massively off. If we assume that Paul Stine was heading back to the theater district after leaving San Francisco International Airport, and Leroy Sweet gave the heading of 500 9th Avenue at 9.45 pm, then we are back to where we started.