Of 1,000 drivers, a total of 57% owned up to leaving less than a two-second gap between themselves and the next vehicle, the research from road safety charity Brake and insurance company Direct Line found.
A total of 28% admitted to tailgating monthly or more often, with men worse offenders than women. Yet the poll also revealed that 95% of drivers worry about tailgating, with 44% concerned most times they drive on a motorway.
The poll also showed that 60% break the 70mph motorway speed limit by 10mph or more, with almost 30% doing so at least monthly.
Brake deputy chief executive Julie Townsend said: "Traffic laws are not just for others; all drivers can help make our motorways safer."