A driver was caught travelling at 159 km/h in a 100 km/h speed zone yesterday evening and is suspected of being under the influence of drugs.
Gardaí from the Buncrana Roads Policing Unit made the detection on the N13.
The motorist then failed a roadside breath test and was found to have cocaine and amphetamines in their system.
They were subsequently arrested and are due to appear in court.
As a result, the driver may be disqualified from driving and face a possible conviction.