The first eyewitnesses to see the Rambler during the crucial period, Peggy and Homer Your, stated that "As they were driving west on Lake Herman Road at the turn off to the Benicia Water Pumping Station, she observed a Rambler station wagon parked with front end heading east (on the east bank), there were two Caucasians in the front seat, male and female, when the lights from the car came upon the station wagon, the male sat up in the seat". Robert Connelly and Frank Gasser left the area after the Your's and stated "that the Rambler was parked on the bank (west bank). That would be on the south side. He did not see any person in the car".
So why had David Faraday changed the position of the Rambler from east bank to west bank between the two sightings? The reason for David relocating the vehicle, one can conclude, was done because David saw the west bank as preferential to him and Betty Lou Jensen. The answer probably lies in the two statements, in which the first stated "when the lights from the car came upon the station wagon, the male sat up in the seat", and the second stated "He did not see any person in the car". We don't have to be Sherlock Holmes to conclude that David Faraday likely moved the Rambler because of the obtrusive nature of car headlights, and thought the west bank provided more privacy. This was the last noted position of the Rambler in the turnout before two vehicles were spotted by James Owen several minutes later. In other words, this was the last noted position of the Rambler in the turnout before the Zodiac Killer arrived. So why do Zodiac researchers assume that David Faraday willingly, of his own volition, relocated the Rambler back to the east bank before Zodiac arrived, rather than just accept that the Rambler was still on the west bank when Zodiac arrived? Probably because it's less complicated to explain.
The Zodiac Killer spots the Rambler on the west bank, so pulls in behind it to restrict its options of escape. He immediately exits his vehicle carrying a flashlight and makes David and Betty think exactly like Michael and Darlene did 6 1/2 months later - that he was a policeman. The Zodiac Killer now has several choices. He can immediately open fire when he arrives at the driver side window of the Rambler, he can ask them to leave their vehicle, or he can instruct them to move their vehicle over to the east bank.
We already know that he wanted them out the vehicle because of what ultimately transpired. This is probably why he didn't immediately shoot them on the west bank. Or extricate them from the Rambler at this location, because his vehicle make and model (and license plate) were in an exposed position relative to the road and any potential eyewitnesses. His best option for concealment was ordering the couple across the turnout so that he could park abreast of the Rambler, to its right side, away from the road. This proved to be a good decision, because James Owen was unable to make out any significant details about the Zodiac Killer's vehicle when he passed the turnout, whereas Robert Connelly was earlier able to describe a light colored 1960 Station Wagon parked on the west bank. So imagine if the Zodiac Killer had decided to commence his attack on the young couple, with his vehicle even closer to the road on the west bank, parked behind the Rambler. His vehicle would have been much more exposed to passing motorists.
There are so many possible variables at this point, it's difficult to be confident on the most probable scenario. Regardless of how and when the shots were fired into the Rambler, it doesn't change the fact that the last position the Rambler was observed alone in the turnout before James Owen passed, was on the west bank by Robert Connelly. This is where we should assume David Faraday and Betty Lou Jensen were when Zodiac arrived, rather than place him back on the east bank for the sake of convenience. This story is much easier to tell with David and Betty on the east bank throughout, but ignoring the eyewitness testimony of Robert Connelly to achieve this, only serves as self-deception. Something that has permeated the Lake Herman Road story ever since Robert Connelly had to insist to the police that the Rambler was on the west bank that night. The widely held narrative from December 21st 1968 to this day, is a Zodiac Killer who drives into the turnout and immediately parks alongside the Rambler to its right. Although this is still possible, it contradicts the last known sighting of the Rambler when sitting alone in the Lake Herman Road turnout.