Police officers have made 29 arrests on South Yorkshire roads since new drug driving legislation came into force last month.
Officers now carry roadside drug testing kits similar to alcohol breathalysers, which screen for illegal substances.
Since new laws were introduced eight weeks ago, meaning drug driving now carries the same penalties as drink driving, officers have conducted 46 tests.
Some 29 returned a positive result for drugs, with all detecting cannabis and five also identifying traces of cocaine.
Five of the tests were carried out following collisions.
Three women and 26 men arrested over the results of their tests have been bailed pending further inquiries.
Temporary inspector for Roads Policing, Steve Askham, said: “Officers were trained and ready to go live with the new roadside drug screening kits last month in line with the additional legislation introduced by the government.
“These arrests are a credit to two of our dedicated officers who have been leading the way with the introduction of the kits and with training the force.
“Over half of those stopped have tested positive for either cannabis and cocaine, and whilst this is a great result for us, it’s very concerning how many people think they are fit to drive with these illegal substances in their system.
“Driving is severely impaired by drugs and anyone who chooses to get behind the wheel of a vehicle while under the influence is not only putting their own life at risk, but the lives of other road users.
“I would strongly urge people to think twice before choosing to drive as the consequences, more often than not, can prove fatal.
“We are determined to make our roads in South Yorkshire safer and protect drivers in our county from irresponsible and thoughtless actions of others.”