Road policing officers are stepping up an operation to reduce collisions and casualties on the A12.
Operation Excellence was launched on March 1 in response to concerns about an increase in crashes and delays on the road.
It is hoped that the operation - which is also targeting criminals using the A12 - will reduce problems by curbing speeding, tailgating and other forms of inconsiderate driving.
The operation is likely to continue for a further six months and will include widespread rush hour patrols from Brentwood to the Suffolk border.
Essex Police Casualty Reduction Manager Adam Pipe said: "There are many motorists who need to change their driving behaviour.
"We have received many complaints about aggressive tailgating, undertaking, speeding and using mobile phones at the wheel. These are all factors that contribute to collisions.
"We have also discovered that some drivers are angered by bad or aggressive driving and end up driving badly themselves.
"If we can change the way that people use the A12 we are convinced that we can reduce collisions which in turn means fewer delays.”
Since the launch of Operation Excellence, 422 people have been stopped for speeding - with some speeds being well over 100mph and 100 people have been stopped for using mobile phones while driving.
Some 67 people were stopped for not using seat belts and 46 were seen tailgating or other forms of careless driving.
Five drivers were found to be uninsured, 12 vehicles had invalid MOTs, one driver was arrested for driving while disqualified, another was arrested for dangerous driving and another driver was arrested for drink-driving.
Police involved in the operation have also recovered a stolen caravan and two items of plant machinery that had been stolen.
Mr Pipe added: ”We have been working closely with Essex County Council and the Highways Agency to reduce crashes and delays on the A12 and the results so far have been encouraging.
"However, crashes are still continuing and they have a knock-on effect by causing gridlock in Chelmsford and towns and villages near the A12.
"By asking drivers to be more careful, more considerate and to be more aware of other road users we believe that safety can be increased on the A12.
"Of the 46 cases of careless driving the majority involved tailgating where impatient drivers were aggressively trying to force others out of the way. People who have been stopped for speeding tend to be impatient drivers or those trying to make up lost time caused by delays.
"We are asking offending drivers on the A12 to make a little sacrifice that will reduce crashes and help everyone in the end. We are asking them to slow down, calm down and to respect other road users. We are sure it will make significant improvements to the A12.”
Cllr Rodney Bass, Cabinet Member for Highways and Transportation at Essex County Council, said, "We are very pleased to support this initiative from Essex Police to reduce casualties on the A12. We will continue to work with the Police and the Highways Agency to drive up standards on this strategically vital road.”