Police said they were treating the incident as attempted murder. Chief Superintendent Alan Marlow, who is leading the hunt, said he was 'astonished by the inhuman, calculating and ruthless nature' of the attack.
The 38-year-old married woman was yesterday recovering at home in Luton, Bedfordshire. 'She is still very traumatised,' Chief Inspector Colin Woolf, of Luton police, said. The two-hour ordeal began shortly before 8pm on Tuesday when she slowed her Vauxhall Astra car in Pasture's Way, Luton, for two youths who were pushing a dark blue or black Ford Escort.
The youths ran over to her car, bundled her into the passenger seat and drove off. They then pulled on balaclavas before forcing her into the back of the car, placing a plastic bag over her head and binding her with a rope. They also took her jewellery.
During her ordeal the woman was sexually assaulted. The youths finally abandoned her, still bound, in the car park of Toddington services on the M1 - eight miles from where she had been ambushed.
Police said the youths splashed a petrol-like liquid in the woman's face and over the back seat of the car, which they then set ablaze before running off.
The woman struggled out of the car before a lorry driver came to her aid.
The attackers were said to be aged 16 to 18, 5ft 7in to 5ft 8in tall. One was wearing a dark leather jacket and one had 'Pete' tattooed on his knuckles.