Police have searched the Lancaster Canal, near to Ashton Basin in Preston, for missing man Connor Hegarty.
The 23-year-old was last seen at around 2.30am on Monday, driving a silver Vauxhall Astra in Tulketh Brow.
His car was later reportedly in a crash near Railway Bridge in Fylde Road, and close to Ashton Basin, police said.
A spokesman said nothing was found during the search, which was carried out today and prompted a number of enquiries from the public.
Officers remain 'very optimistic' about finding Connor, who was wearing a white t-shirt and black jeans, safe and well, he added.
Earlier this week, PC Amy Cooney, of Preston Police, said in a statement: "Connor has been missing for several days now and we are concerned for his welfare.
“If you have seen him, or know where he is, please contact police.
“Furthermore, I would urge Connor, if he sees this appeal, to contact us to let officers know he is safe and well.”
Anyone with information can contact police on 101, quoting log reference 0530 of August 6.