Fears drivers ignoring one-way signs will cause an accident during roadworks at Guardbridge have prompted a warning from police.
Motorists have reported meeting vehicles going the wrong way on the rural road between the village and Balmullo.
The route, known as the Pusk road, is one-way while Main Street is shut for eight weeks with a seven-mile diversion for those travelling between St Andrews and Dundee.
Police Scotland warned that disobeying the one-way signs was very dangerous and anyone caught would be charged.
Sergeant Pat Turner of St Andrews Police Station said he was aware of issues on the narrow road which is used by buses as well as cars.
He said: “Ignoring traffic signs can have severe consequences.
“They are there for a reason and we would urge road users to be responsible.”
Frustrated motorists took to social media to warn others and told of near-misses and angry exchanges.
Silvia Brill posted: “I nearly got taken out in the Pusk road a with a driver going the wrong way. Why is this not being policed?”
She said when she told the driver he was going the wrong way he swore at her.
Margaret Lackie witnessed three cars coming down the short stretch of road the wrong way yesterday and one the day before.
She wrote: “Why is nobody checking on this before there is an accident?”
Advising drivers to take care, Dave Smith said he was surprised to meet two “idiots” travelling from Balmullo to Leuchars against the traffic.
He said: “Signage is all in place, you can’t miss it, so this was no mistake.”
Main Street closed on Monday to allow a pipe to be laid between St Andrews University’s green energy centre being created at the former paper mill and the North Haugh.
It will carry hot water from a biomass boiler to heat university buildings.
A university spokesman said overall traffic flow had improved over the course of the week as drivers became familiar with the diversions and traffic management.
He said: “Traffic flows have been monitored closely by Fife Council and contractors and where necessary additional measures including additional signage have been taken to minimise congestion.
“Diversion routes will continue to be monitored for the duration of the road closure at Guardbridge.
“We completely understand the frustration of those affected by the road works and we are grateful for the patience, understanding and good grace shown by road users.”