In general, all licence plates numbers in Singapore come with the vehicular registration number, suffixed by the official reference in the form of a letter of the alphabet. Two colouring schemes are in use: the black on white(front) with black on yellow(rear) scheme or the older white on black scheme. The number plate has to be made of a reflective plastic or metallic with textured characters made of black (for white-yellow) or white or silver (for black ones). No standardised typeface is used and all are based on the Charles Wright number plate typeface used in the UK, from thinner looking variants used commonly by SBS buses, taxis and goods vehicles, and even the FE-Schrift font used in Germany can sometimes, though rarely, be seen - though this is prohibited by LTA.
Private car licence plate numbers began in the early 1900s when Singapore was one of the four Straits Settlements, with a single prefix 'S', then adding a suffix letter S 'A' to S 'Y', but skipping a few like S 'H' and S 'Z' (reserved for taxis and buses), S 'D' (reserved for municipal vehicles), and S 'G' for goods vehicles large and small. No changes were made when Singapore became independent in 1965. Later, the suffix was added. Previously there was no suffix, for example, SS1234, as in the vehicle registration plates of Malaysia.
When 'S' was exhausted at SY, in January 1972, Private cars started with E, Motorbikes with A and Goods Vehicles under 3 tonnes with Y. E was followed by EA, EB with the letters EC in 1973 up to EZ. From 1984, the "S" series of number plates was launched again, but now with two serial suffix letters, starting from SBA. Currently, as of this writing, the SKJ series is in issue for private cars.
Other classes of vehicles have registration numbers beginning with specific letters:
In addition, the following are controlled for specific types of vehicles, including:
Special prefixes were used for specific events, such as:
They are never used after the events.
Civil Mobilisation Exercise or Vehicle Recalls have a large A3/A2 sticker stuck at the rear and front of the vehicle denoted that the vehicle is being deployed or mobilised for civil 'emergencies'. These usually happens during weekends.
The checksum letter is calculated by converting the letters into numbers, i.e. where A=1 and Z=26, potentially giving 7 individual numbers from each registration plate. However, only two letters of the prefix are used in the checksum, for now, so the first letter is discarded for a three-letter prefix. SBA 1234 would therefore give 2, 1, 1, 2, 3 and 4 (note that "S" is discarded). Each individual number is then multiplied by 6 fixed numbers (9, 4, 5, 4, 3, 2). These are added up, then divided by 19. The remainder corresponds to one of the 19 letters used (A, Z, Y, X, U, T, S, R, P, M, L, K, J, H, G, E, D, C, B), with "A" corresponding to a remainder of 0. In the case of SBA 1234, the final letter should be a G.
There was some speculation as to whether the Singapore government would continue the SDZ series to its next logical sequence - i.e. SEA and then on to SEY etc.. Apparently the government decided to adopt the policy of using no vowels in the middle digit to avoid meaningful 3 letter word combinations. Indeed there was never an SA sequence issued (the S—sequence started with SBA), although this was because the West Coast Division of Sabah state in Malaysia has been using the SA sequence.
The Land Transport Authority has announced they may begin implementing the use of personal registration licence plates (Vanity plates) as early as late 2007, and are currently working on the details of the plan. These licence plates may take up to 12 characters compared to the current eight. For now, there is a thriving trade in the sale of number plates that have significant digits (i.e. lucky numbers) or letter combinations like SGD. Full vanity plates are not available in Singapore, only the number combination like Germany.
Vehicles registered as "Off-peak Vehicles", affectionately known as "Weekend Cars", pay a cheaper road tax as compared to normal private cars, although COE charges apply as usual. They display number plates with white characters on a red background. These vehicles are only allowed to run on the roads in Singapore after office hours (7pm-7am) on weekdays, full day on Saturday, Sunday and Public Holidays.
In the case where owners of private vehicles choose to run on the roads on weekdays during office hours, they are required to buy an e-licence for $20 either online or through major post offices. Car owners have up to 24 hours on the following day to purchase the e-licence. Failure to do so first time offenders may be fined up to $5,000 for failing to display a valid day coupon or using an invalid day coupon, and fined up to $10,000 for using an altered day coupon when the OPC is used during the restricted hours.
Off-peak vehicles pay a relatively lower road tax (a discount of up to $500) as compared to other private vehicles and are also given rebate of $17,000 which can be offset against COE and ARF.
Even so, the majority of the people in Singapore do not use Off-peak vehicles.
Light Goods Vehicles and Goods Passenger Vehicles uses the G series prefix. From G to GA through GZ, and the GBA, current issue is GBC.
"Restricted Use" vehicles display a number plate with a diagonal red over emerald green pattern with white letters with the two lead characters "RU". Motorcycles registered as these vehicles also use these.
"Classic Car" collectors' vehicles display a normal registration but with white lettering on a half-red over half-yellow background, with seal affixed on number plate by an authorised inspection centre. Motorcycles registered as these vehicles also use these.
"Hazardous Cargo" plates were introduced in 2005, using normal commercial vehicle registrations, often in the 'Y' code, but with, unusually, with black figures on a reflective orange background. These trucks are permitted to carry fuel, gas canisters and chemicals (inflammables), and are not permitted to enter tunnels, nor the city areas unless route arrangements have been pre-made with the fire services. Malaysian Lorries are also required to have a separate HAZMAT Orange License plate affixed to both the Trailer and Wagon (Tow Head) and subjective to the same rules.
"Research and Development" vehicles display a plate with a diagonal yellow over blue pattern with prefix 'RD'
Motor Dealers and Traders use white on blue plates using post fix code S, preceded by up to 4 numerals for their test drive vehicles such as 1234 S.