Some drivers ignorant, some just nasty
The director and owner of private emergency service, AME Ambulance Services Arthur Toh, prefers to "bite the bullet" instead of report obstructions.
"There is nothing much we can do, even if we lodge a report," Mr Toh, 59, said.
"Usually, I just bite the bullet and let it go."
Why do some people not give way?
It is mostly because of ignorance, he said.
"Most people don't give way because they don't know. But some of them are just nasty people."
It is also uncommon for an ambulance to use a loudhailer, even in critical situations.
"Every ambulance is equipped with a loudhailer," said Mr Toh.
"But in all my 10 years of driving an ambulance, I have never heard of anyone using it.
"For that driver to have used it, he must have been very frustrated."
Mr Toh said that he encounters inconsiderate drivers at most once or twice a month.
For Mr Sivachandran Murugasu, however, it is a common occurrence in his 11 years of driving an ambulance.
The founder of nursing company Abella Agency said: "It happens about three out of the five times I drive."
The 32-year-old recounted an incident last year when a taxi driver refused to give way despite the ambulance flashing beacon lights and blasting the sirens.
This happened along the Central Expressway towards Ang Mo Kio.
Mr Sivachandran said: "When our vehicles finally exited the tunnel, the taxi driver even flashed his middle finger at me."
He later lodged a complaint against him.
Mr Sivachandran uses beacon lights and sirens only during emergencies.
"These include situations when the patient has collapsed, has breathing difficulties or is bleeding profusely."
But he feels that vehicles should give way as long as the ambulance is driving in the first lane.
He said: "The main priority for us is to send patients to the hospital quickly to get assistance.
"For patients in critical condition, a slight delay can cost their lives."