Alarm over reports of Lincolnshire 'seatbelt chicken'
Road safety campaigners are concerned about young people in Lincolnshire "playing chicken" and refusing to wear seatbelts.
Lincolnshire Road Safety Partnership said youngsters were not buckling up to avoid being teased.
Spokesman John Siddle said the trend of "playing chicken" - where someone is dared to do something dangerous - was "quite alarming".
"It is difficult to understand why they are doing it," he added.
Mr Siddle said police officers had told him that peer pressure often results in young people refusing to wear seatbelts.
Postmen and delivery staff are exempt from wearing seatbelts if they are delivering to locations close to each other - less than 50m away.
Kevin Clinton of the Royal Society for the Prevention of Accidents (Rospa) said: "There is a myth that you do not need to wear a seatbelt in the rear of the car but that is absolutely not true.
"If there is a crash and you are in the back seat without a seatbelt you will be thrown forward with the force of a small elephant."
He added: "It is more likely that a group of young men in a car will not wear a seatbelt."