Avon and Somerset Constabulary are appealing to motorists for dashcam footage of an incident which happened near to the Almondsbury motorway interchange.
The incident happened on November 19 between 4.30pm and 5pm.
Two vehicles - a car and a lorry - were travelling along the M4 in a westbound direction.
Both vehicles were then stopped and the lorry driver approached the car driver before remonstrating with him and driving off.
Avon and Somerset Constabulary are keen to hear from anyone who may have dashcam footage of this incident.
The police have said that no one was injured but they need to speak to the lorry driver.
If you have any additional information, you are urged to contact the police, quoting reference number 5219268041.
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