Almost 1 in ten women have admitted to wearing a seatbelt under their arm to protect their fake tan while 7% say it's to protect their outfit.
The RSA has launched a campaign to encourage women to wear their seatbelt correctly across their body, to protect them from serious injury and death.
A study of 300 woman aged 17 to 34 shows that 28% admitted to not belting up correctly.
The main reasons were to relieve neck tension followed by general comfort.
Moyagh Murdock, Chief Executive of the RSA, said: “Worryingly, whether for comfort or vanity, many women choose to wear their seatbelts under the arm, instead of over the shoulder, which exposes them to terrible injuries and even death in the event of a crash.
She added: "Placing the shoulder strap of the seatbelt under their arm leaves your upper torso — including your neck, face and head — completely unrestrained during a collision.”