Metropolitan Police Bureau deputy traffic commissioner Adul Narongsak said his idea was "not an urgent policy".
The officer revealed the plan on Monday. It immediately sparked a deluge of negative feedback from car users.
Pol Maj Gen Adul told police that owners of vehicles which have been used for more than a decade should be forced to pay higher annual registration fees. The fees would be equal to those imposed on brand-new vehicles.
The proposal emerged when he laid out urgent traffic solutions for Bangkok which are set to be implemented before the school term resumes next month.
He said he will discuss the idea with representatives of other police and government agencies, the media, the private sector, and the transport sector, and their conclusions can be presented to the government later.
However, Pol Maj Gen Adul insisted that old vehicles increased traffic congestion in Bangkok when they broke down and he intended "to solve problems, not create them".
He said he got the idea from Japan and that it would help alleviate traffic congestion, adding that he believes a thorough study of the idea - including its economic effects - will bring about the best solution.
Pol Maj Gen Adul's traffic-busting measures include harsh fines for traffic violators and even imprisonment. Illegally parked vehicles would be towed away rather than being clamped.
Criticism of the idea came thick and fast, particularly on online social networks.
Thousands of comments were posted on almost every popular chat web page overnight.
"I think perhaps this is another policeman who needs brain surgery. So an old car which has been carefully maintained will be banned. What nonsense. Stop the government's loony populist policy of encouraging cheaper ways to buy new cars for first-time buyers," Beerboy wrote on the Bangkok Post website.
"As happens so often in Thailand, we are given a reason which does not quite make sense. This invariably means there is a real reason behind it which has something to do with someone making money. I have been in countless jams in Bangkok and don't recall ever seeing the cause to be an old car. The most common things jamming it up are simply selfish drivers who don't care _ such as parking two abreast at the side of the road or blocking the lane to do a U-turn where they shouldn't. These are [the people] who should be getting tickets," another reader, Bewildered, wrote.
In a street survey, Yodpao Tubpuang, a university student, questioned how the idea could be implemented.
"It is nice in the way of environmental issues because old cars often give out black smoke and pollute the air," he said. "But practically, for Thai people, it is difficult to buy a new car every 10 years with their wages since most of them are in the middle class. The policy will not help relieve the traffic jams or solve anything."
Rungrueng Patthammaroj, an official at the Ministry of Natural Resources and Environment agreed with the policy although he is now driving a 12-year-old car to work.
"A car older than 10 years should not be on the road since it can easily develop mechanical problems and cause traffic congestion," Mr Rungrueng said.
"If people take good care of their cars then they will be good to use. But I believe that most people do not. If the policy is really implemented, I will have to accept it and buy a new car.
"However, I still do not believe it will solve traffic congestion problems."