Pc Alastair Bain, 51, told the High Court in Edinburgh that he and colleagues re-staged a journey to Argyll which David Gilroy, 49, made the day after Suzanne went missing.
The police constable told prosecution lawyer Alex Prentice QC that officers wanted to establish how long it would take to travel between Edinburgh and Lochgilphead.
Earlier Pc Bain revealed that they could not use Gilroy’s silver Vauxhall Vectra in the reconstruction because it was not road-worthy. And he told the court that while Gilroy took almost five and a half hours to travel between Argyll and Edinburgh, he could make the same journey in around three hours and 11 minutes.
Pc Bain told the court that police had to borrow a similar model of vehicle from a member of the public.
The evidence came on the 14th day of the trial of Gilroy, who denies murdering Suzanne, 38, in Edinburgh city centre almost two years ago.
Pc Bain said officers in charge of the probe into Suzanne’s disappearance asked him to re-stage a journey made by Gilroy on May 5, 2010.
Gilroy travelled from Edinburgh to a school in Lochgilphead, Argyll, just 24 hours after Suzanne was last seen in the Capital.
Detectives wanted to compare the time it would take to make the journey with the time it took Gilroy.
The police established the time it took Gilroy to travel from Lochgilphead to attend a voluntary police interview in Edinburgh based on information gleaned from CCTV cameras.
But Pc Bain said they could not use Mr Gilroy’s silver Vauxhall Vectra because of damage to key parts of his vehicle’s suspension.
On Wednesday, Pc Bain told Mr Prentice that the damage to the car suggested that Gilroy had been driving off road.
Yesterday, Mr Prentice asked why Pc Bain had to obtain a similar model of car from a member of the public.
Pc Bain replied: “It [Gilroy’s car] was deemed unsafe to be driven.”
Pc Bain told the court that officers then re-staged the journey between Edinburgh and Argyll on three different occasions between June 23 and June 24, 2010.
From Edinburgh to Argyll, the police officer said he completed his journey in around three hours.
From CCTV footage, police thought Gilroy did the same journey in around five hours and eight minutes.
Pc Bain then told the court that he returned to Edinburgh also in just over three hours. For the same journey, Gilroy is thought to have taken five hours and 29 minutes.
Earlier in the day, judge Lord Bracadale told members of the jury that some of them had been given a part of a document which they were not supposed to see.
The judge told the jurors to disregard any information which they may have learned from the document and to base their opinion solely on the evidence led in court.
Gilroy, of Silverknowes, Edinburgh, has pleaded not guilty to murdering Suzanne in Thistle Street, Edinburgh or at another location in Scotland by means unknown to the prosecutor on May 4, 2010.
He has also pleaded not guilty to four other charges which allege he committed a series of criminal acts at various addresses in Scotland between August 2009 and June 2010.
The trial continues.