Mr Sainsbury did not call any evidence for the defence and said the case "factually then comes down to what can be made of comments he (Woods) made to various people at the scene".
Mr Sainsbury said those comments, in the context of a concussion, "make perfect sense and are not indicative of 'I was driving at the time of the crash'".
For the prosecution, Mr Eden said there was some physical evidence to suggest Ms Jessop could not have been the driver, such as the fact the driver's seat was back at its fullest extent, when she was just 164cm tall.
Woods' blood-alcohol level had been taken six hours after the crash, when it was found to be 12mg. The new legal limit is 50mg.
"Even at conservative dissipation, that would have put him over the legal limit at the time of the crash".
Mr Eden said Woods' police interview had been taken "a couple of months after the accident", and "by then he knows that Ms Jessop is dead".
"The story about the swap-over is just that."
Judge Morris said the sole issue was whether police had proved beyond reasonable doubt that Woods drove at the time of the crash, "or, to put it another way, whether there is a reasonable possibility that Ms Jessop was driving".
The judge said no one saw who was driving the car earlier, no one saw the crash happen, and "both the driver and the passenger were propelled from the vehicle".
Given that Woods later told police he had swapped places and was not driving at the time of the crash, Judge Morris asked, "How then does the prosecution say it can prove beyond reasonable doubt Mr Woods was driving?
"Essentially the prosecution case relies on what police say are admissions at the scene," the judge said.
"Really, this case does come down to whether I can safely rely on those comments as reliable admissions.
"The police say these are compelling admissions from a young man feeling guilty about the carnage he had caused around him ...
"Police say his immediate reaction is the more reliable ...
"The later claims police say are retrospective reconstructions to avoid responsibility."
Judge Morris said a medical witness had been asked what effect an injury such as concussion would have on the reliability of statements a person made.
"The doctor couldn't answer that ... I have to provide an answer to that," the judge said.
"This is not a trial by expert, and a lack of opinion by an expert is not determinative, but it is a factor."
The judge said the placement of where Woods and Ms Jessop were found at the crash scene did not help to determine who had been driving, and "the pathology doesn't help, either".
The judge said the medical evidence given by Dr Sarah Clarke was that memory of events leading up to a crash could be forgotten but recovered later.
Woods' police interview, Judge Morris said, "is consistent with that medical scenario".
The judge said it would be "naive not to consider" the possibility that Woods had changed his story after the crash to avoid responsibility. "The interview is consistent with either of those explanations and I cannot tell which."
The judge said the car had run off the road on a slight bend, and "there was inattention here".
She said a defence submission that this indicated an inexperienced driver, such as Ms Jessop, was "speculation and doesn't assist".
Judge Morris said the defence had pointed to blood and blond hair being found on the car in a position that indicated Woods, who was blond, might have exited from the passenger seat.
Besides the statements made at the crash, the judge said, "there are insufficient other circumstances either for the prosecution or the defence to assist."
"The charge must be dismissed, even though I know this dismissal will be difficult for Ms Jessop's family."
The judge thanked Mr Sainsbury for the "many helpful concessions" which had reduced the amount of evidence needed to be called in court.
