In Singapore, leaving a car running while parked may seem harmless, especially when the air conditioning is on and the driver only plans to wait a few minutes. Depending on the circumstances, though, it can be an offence.
Singapore regulates vehicle idling under Regulation 21 of its Environmental Protection and Management (Vehicular Emissions). A driver may not leave the engine running while the vehicle is stationary, unless it is stopped because of traffic conditions or falls under one of the specified exceptions.
The rule also covers other machinery attached to the vehicle, not just the engine that drives it. A parked car with its engine on is therefore treated differently from a vehicle that is stationary because of traffic conditions, such as while waiting in a queue.
Regulation 21 does not specify a minimum waiting time before the requirement to switch off the engine applies.
Why Idling Is Regulated
The rule is part of Singapore's wider effort to control air pollution from vehicles.
The aim is to minimise pollution and reduce fuel wastage. An idling engine keeps producing exhaust even when the car isn't moving, and someone sitting in an air-conditioned cabin can easily forget that those emissions still enter the surrounding air.
NEA also regularly reminds motorists to switch off their engines when their vehicles are stationary.
The idling rule sits in the same set of regulations as rules covering smoky vehicles and excessive vehicle noise. The Environmental Protection and Management (Vehicular Emissions) Regulations also set standards for exhaust emissions from new and in-use vehicles.
Fines and Enforcement
A driver convicted in court can be fined up to S$2,000 (roughly US$1,560) for a first offence and up to S$5,000 (roughly US$3,900) for a second or subsequent conviction, according to NEA.
These are the maximum penalties set out in the regulations and apply to other offences under them as well, including offences involving smoky vehicles. NEA also states that motorists may be offered a composition fine, or be taken to court.
The idling rule has been in force since 1999, when the Environmental Protection and Management (Vehicular Emissions) Regulations came into effect.
NEA took enforcement action against 3,800 motorists in 2020 and 3,500 in 2021 for idling engine offences. The agency regularly monitors areas where motorists are more likely to leave their engines running and takes enforcement action against offenders.
Members of the public can also report idling vehicles through NEA's online feedback form or the myENV app, providing details such as the vehicle registration number, location, date and time.
Regulation 21A also places a duty on vehicle owners to provide information about the alleged offender when required by NEA. The information must be provided within seven days, and failing to do so without a valid reason is a separate offence. Knowingly providing false or misleading information is also an offence.
Exemptions
Not every stop requires switching off the engine. Waiting at a traffic light falls under the traffic conditions exception, so a car stopped at a red light is treated differently from one parked by the roadside with its engine running.
NEA lists several other exemptions, including vehicles whose engines power on-board equipment (refrigerated trucks, for example), vehicles undergoing inspection or repair, and enforcement or emergency vehicles.
The regulation also allows the machinery to remain running when examination or operation is necessary because of a failure or breakdown, or when the machinery is required for an ancillary purpose.
Electric vehicles fall outside the rule. In a Written Parliamentary Reply in February 2023, Singapore's then Minister for Sustainability and the Environment Grace Fu said that Regulation 21 does not apply to electric vehicles because their electric motors stop when the vehicle is stationary.
