Under the UK's first car share motorway scheme, a lane will operate at peak times in the morning and evening rush hours for cars with two or more people between St Albans, Hertfordshire, and Luton, Bedfordshire (junction 7 to 10).
If it is successful, the lane will be extended. Darling said work would begin next autumn and was expected to be completed by 2008.
The dedicated lane, which will cost £1m, will only operate at peak times and solo car drivers will able to use it at other times.
The Government estimates at least 5% and up to 10% of drivers may chose to car share. Cameras will not be used to trap offenders but police will be able to pull over those they suspect of misusing the lane. The penalty has not been announced.
Darling says: "The Government is determined to tackle congestion - adding capacity where necessary and making better use of existing road space. These lanes have been used to great effect both in America and Australia and could play a key role in reducing congestion on Britain's motorways."
Car-sharing lanes on the M61 and M62 will also now be investigated. Work to widen the M1 was already planned before the scheme was introduced.
The plans were welcomed by Transport 2000 and the RAC Foundation