The proposed system would use “COE credits” instead of cash for bidding, with more credits given to those with a greater need to own a vehicle. SINGAPORE: The proposal by the Progress Singapore Party (PSP) to set up a certificate of entitlement (COE) credit system may be well-intentioned, but is “unlikely to be effective in practice”, said Senior Minister of State for Transport Amy Khor. She was responding to suggestions by PSP on how to create a more equitable COE system for private vehicles