A woman in her 70s is in critical condition after a serious two-car crash in Ballyshannon, Co Donegal.She is receiving treatment at Beaumont Hospital in Dublin after the incident, which took place before 10pm on Saturday, July 25th. She was a passenger in one of the cars. Two other passengers in the car were brought by ambulance to Sligo University Hospital for treatment of non-life-threatening injuries, while the driver and two passengers in the other car were also treated for injuries. A man in his 40s was arrested at the scene and released without charge pending analysis of a sample by the Medical Bureau of Road Safety.Gardaí are appealing for witnesses who were in the area of the Erne roundabout in Ballyshannon between 9.45pm and 10pm on Saturday July 25th. They are asked to share dashcam footage if available.A Garda roads policing operation is meanwhile in effect for the bank holiday weekend, running from Thursday until Tuesday.There were no fatalities on the first day of the operation, an update by Garda headquarters revealed. A total of 20 people were arrested for driving under the influence and more than 750 drivers were detected for speeding offences. Another 90 cases were detected without a seat belt or while using a mobile phone.The operation includes high-visibility checkpoints and intoxicant testing. Notable speeds detected included a vehicle travelling at 90km/h in a 50km/h zone in Kilmaley, Co Clare; a vehicle driving 114km/h in a 60km/h zone on the Navan Road in Dublin; and a vehicle travelling 139km/h in a 100km/h zone on the N7 at Johnstown, Co Kildare.[ I am a detective garda. Here’s why an e-scooter ban is unenforceableOpens in new window ]