The number of specialist roads officers was slashed by almost three-quarters in some parts of the country in 2016, and shrank in all but seven areas.
Northamptonshire saw the biggest cut at 74 per cent, followed by Norfolk (65 per cent) and West Yorkshire (50 per cent).
The total number of specialist roads officers across all 43 forces fell from 5,237 to 4,934, according to data released by policing minister Brandon Lewis in response to a parliamentary question.
The Government has announced a number of policies in recent months to crack down on reckless motorists, such as tougher penalties for killer drivers and those using hand-held mobile phones.
But motoring groups expressed concern that harsher rules will not change driver behaviour unless there is sufficient enforcement.
Steve Gooding, director of research charity the RAC Foundation, described cuts in dedicated officers among forces as “concerning and in some cases extremely alarming”.
He said: “Next month the penalties for using a handheld mobile at the wheel will double, but stricter laws are of little deterrent if drivers don’t believe they will be caught.”
Home Office data shows 16,900 drivers were handed fixed penalty notices for illegally using a phone in England and Wales in 2015, compared with 123,100 in 2011.
Jayne Willetts, lead for roads policing for the Police Federation of England and Wales, said roads policing officers are “specialists in their field” at tackling incidents such as speeding, tailgating and other criminality on highways.
She went on: “The thin blue line is now so thin on our roads system that we are almost to the point of being invisible.
“We should be looking to invest in more of these highly trained, specialist officers.”
Suzette Davenport, National Police Chiefs’ Council lead for roads policing, said individual forces decide how best to allocate their resources.
“Some may choose to reduce the numbers of specialist traffic officers but this does not mean that their roads are not adequately policed,” she insisted.
“They can deploy a range of resources, including ANPR (automatic number plate recognition) technology, targeted patrols using unmarked vans, high vantage points and helmet cams to catch offenders.”
Mr Lewis said some forces were unable to make a clear distinction between functions carried out by their officers, particularly for units providing both roads and armed response policing.
He added that reclassification of roles can cause fluctuations in figures from year to year.
A West Yorkshire Police spokesman said the force has lost over 1,000 officers and 2,000 staff since 2010.
“Road safety remains an important policing service but the cuts have required us to reorganise our force structure to move from having specialist teams such as roads policing, firearms and dogs, to more flexible mixed speciality based units.”
Norfolk Police chief inspector Kris Barnard said 104 armed response vehicle operators also perform roads policing tasks across Norfolk and Suffolk.