Officers were alerted to an impaired driver entering Amersham via the A413 on Thursday (28/4).
One Roads Policing officer deployed their Eco-friendly on foot from the base and was backed up by another Roads Policing crew.
After the vehicle was stopped by their new foot unit, they issued a drug wipe.
The driver failed after providing a positive preliminary saliva sample for cannabis and was arrested for driving whilst over the specified limit of cannabis.
The driver has been taken to custody where they provided a sample of blood for analysis.