The 57-year-old was with his 14-year-old daughter and her friend on the A435 from Mappleborough Green on Friday (July 10) when he noticed a black Peugeot 608 driving erratically.
About 6.05pm the Peugeot pulled up alongside him at the M42 Junction 3 roundabout where the driver shouted racial abuse.
As the two vehicles drove over the M42 bridge, the man continued to racially abuse the victim and this carried on until the Maypole island where traffic came to a standstill.
The man then threatened to kill the victim, got out of his vehicle and began to approach the dad before he managed to drive away.
No one was injured during the incident but the victim and the two girls were left very shaken, distressed and frightened.
He is white, 40 to 45 years old, of a big build, with short light brown hair and clean shaven.
He had puffy facial features and was wearing a long sleeved white buttoned shirt and brown trousers.
Anyone with any information should call police on 101 or Crimestoppers anonymously on 0800 555 111.