The ad for the Volvo C30, created by Abbott Mead Vickers BBDO, received three complaints from viewers who thought it was inappropriate for broadcast during the day.
The TV ad shows a car parked on grass in bright sunshine in front of a picket fence with a rabbit in the foreground and then the scene changes to show the same car at night on dead leaves with the rabbit replaced by a snarling rodent.
It switches between the two scenes several times, with the final switch including the words "Love it?" and "Hate it?" over the car in the bright and dark scenes respectively and a voiceover states "The new Volvo C30, what do you think?".
The Advertising Standards Authority rejected the complaint because it thought the image was likely to be interpreted as light-hearted by the majority of viewers and that the rodent, although snarling, was likely to be viewed as comical rather than seriously threatening.
The watchdog concluded that the ad was unlikely to cause distress to either adults or children and was not inappropriately scheduled.
In a separate adjudication, the ASA has upheld complaints about a direct mail campaign for Childline, which contained a mock counsellor log sheet that some recipients believed to be genuine.
The mailing, created by WWAV Rapp Collins, received three complaints saying it was misleading and irresponsible and would cause undue distress or fear, especially to those who had suffered abuse.
The mailing contained a letter and a mock counsellor log sheet, which included handwritten details of three calls to Childline with text such as: "Fact. Father violent towards step-mother after drinking: abusive, shouting, punching. Sometimes XXX is the subject of arguments, so blames himself for fighting and violence."
The NSPCC believed that the ad made clear it had not been targeted to a specific person and pointed out that there was no name or address on the letter or the envelope.
The ASA upheld the complaints and told the NSPCC to make clear on the envelope that it contained marketing material and to make clear on the counsellor log sheet that the calls were not genuine.