A drink-driver sped at 100mph (160km/h) and hit another car head-on, killing its driver and himself, an inquest heard.
Anthony Southwood, 72, swerved on a roundabout shortly before the crash on the A5183 between Redbourn and St Albans, Herts, on 9 October 2019.
His car hit a Peugeot driven by Gillian Williams, 55, of, Dunstable, Beds.
Both died of multiple injuries resulting from the crash, coroner Geoffrey Sullivan concluded.
According to a written statement from his wife, read to Hatfield Coroner's Court, company director Mr Southwood, of Redbourn, had drunk whisky and taken decongestant before going for a drive in his Mercedes because he had difficulty sleeping.
The crash took place at 23:45 GMT.
"Mrs Williams was travelling north. She was entirely in her lane and driving within the 50mph [80km/h] speed limit," said Mr Sullivan.
Mr Southwood was driving south and had moved lanes so that he "was positioned straight into the path of the car Mrs Williams was driving".
"The two cars impacted head-on," Mr Sullivan added.
From a CCTV camera at a local pub, police were able to calculate Mr Southwood's speed at about 100mph.
Post-mortem examinations revealed Mr Southwood, who was diabetic, was over the drink-drive limit and had a high level of glucose and prescription drugs in his blood, and that Mrs Williams was "essentially healthy".
Speaking after the hearing, Mrs Williams' daughter, Whitney Hughes, described her mother as "a lovely soul", who "worked hard and lived life to the fullest".
She has begun a petition to see speed cameras installed on the stretch.
"I don't want her death to mean nothing," she told the BBC.
"So many have died on that road - growing up I knew how dangerous that road was. Something needs to be done."
The coroner dismissed claims the condition of the road was a factor, and said speed and alcohol were the issue.
But he said he would ask police to investigate claims drivers were flouting the 50mph limit and whether average speed cameras would help.