In a new survey of drivers, six in 10 respondents admitted to tailgating and a similar proportion to breaking the speed limit by 10mph or more on motorways and 70mph dual carriageways.
The survey by Brake also indicates that men are “by far the worst offenders”.
Despite the fact that 57% admitted doing so, 95% of respondents said they are “at least occasionally concerned about vehicles too close behind them”; and 44% said they are concerned “every, or most, times they drive on a motorway”.
Brake says that by “driving too close to the vehicle in front and breaking the speed limit, drivers are leaving themselves far too little time to react in an emergency, risking devastating crashes”. The charity says that crashes on 70mph roads are more than twice as likely to result in death as crashes on roads with lower speed limits.
Julie Townsend, deputy chief executive of Brake, said: "Almost all drivers are concerned about the danger posed by other people tailgating on motorways, and yet a shockingly high proportion admit driving too close and speeding themselves.
“There are no two ways about it: ignore the two-second rule or the speed limit on motorways and you’re putting yourself and others at risk of a horrific crash.
“Traffic laws are not just for other people: all drivers can help make our motorways safer and prevent needless tragedies by committing to keep your distance and stay under speed limits, including temporary lower limits."
Simon Sheldon-Wilson, traffic management director at the Highways Agency, said: "We support Brake’s advice to keep a safe distance from the car in front and to adhere to fixed and variable speed limits."