More than 200 motorists were over the weekend caught unaware after the police reinstated roadblocks on various parts of the city to impose mandatory breathalyser tests.
Most of the drivers spent their nights in custody and some released on Sh20,000 cash bail after they failed the tests.
Relatives and friends of those affected thronged police stations in efforts to seek their release.
Police said the tests will be imposed on various roads after the new law governing the practice was ratified at various levels.
“We will be all over at any time. We have all the needed gadgets to carry out the operations for the sake of the road users in general,” Nairobi police boss James Mugera said.
Those caught are expected in court on November 7 to face the charges of driving under the influence of alcohol.
The developments came after President Uhuru Kenyatta in June 2022 signed the Traffic (Amendment) Bill 2021 into law.
Under the new law, motorists found guilty of drunk driving risk a fine not exceeding Sh100,000, a two-year prison term, or both.
A breathalyser estimates the alcohol content in one's blood from a breath sample.
No driver is allowed to handle a vehicle if they have consumed alcohol in excess of 35 microgrammes per 100 millilitres of breath, 80 milligrammes of alcohol per 100 millilitres of blood and 107 milligrammes of alcohol per 100 millilitres of urine.
“A person who, when driving or attempting to drive, or in charge of a motor vehicle on a road or other public place is under the influence of an alcoholic drink or a drug beyond the prescribed limits, shall be guilty of an offence,” it says.
Drivers of private vehicles are allowed 0.35 micrograms maximum intoxication, while those operating public service vehicles are completely prohibited from taking liquor and their test result should be zero.
The new law is an improvement of another following a court order that had in 2017 declared the use of the alcoblow illegal.
In April, 2017, Appeal judges GBM Kariuki, Festus Azangalala and Fatuma Sichale ruled that the law that introduced the alcoblow was illegal because it violated the Traffic Act.
Part of the draft regulations say refusal to provide a specimen when required to do so by a police officer in uniform shall be an offence and a person shall be deemed to be over the prescribed limit and subject to a penalty which deems one as guilty of the offence.