Modding: A guide for young drivers

//Modding: A guide for young drivers

Modding: A guide for young drivers


Many car enthusiasts may wish to make modifications to their vehicles.

The information and guidelines below will help you to understand which modifications are acceptable and which ones constitute an offence.

PSNI remind you that your driving licence is a privilege and not a right and that driving responsibly in roadworthy vehicles keeps our roads safe and helps to prevent collisions.


Common vehicle modifications:


The vast majority of large or big bore exhausts are illegal for use on public roads. The fact they may have passed an MOT test is irrelevant as this only checks for exhaust gasses and emission legislation compliance.

Big bore and sports exhaust systems are usually fitted to increase the sound emitted and this contravenes the Type Approval of the vehicle, which is an offence.

There is no requirement for a police officer to measure the sound level from the exhaust system, it only requires an opinion that the system is not standard and that it is noisier than a normal vehicle of the same specification.

It is not an offence to sell these exhaust systems, but it is an offence to fit one to your vehicle and drive it on a public road. Motorists who do so could be reported to court and may face a fine and court costs.

Tinted Windows:

Heavily-tinted windows will seriously reduce your view in certain weather conditions and most definitely at night time.

The legal requirements allowed are 75 per cent of light through the front windscreen and 70 per cent of light through any glass either side of the driver’s head.

Any rear door glasses and rear window are not included in this requirement so they can be as heavily tinted as you like.


We do have instruments which can now measure the severity of a tinted window. If a window is found to be too heavily tinted the motorist could be subject to a £30 non endorsable Fixed Penalty Notice and issued with a notice to remedy the fault or in some cases,reported to court.

Lighting Offences:

Blue lights – Under the Road Vehicles Lighting Regulations (NI) 2000, it states “except for emergency vehicles it is an offence to fit a blue warning beacon or special warning lamp or device resembling such whether working or not”

Fog lights – For vehicles fitted with front fog lights (rear fog lights are also included), it is an offence to illuminate them unless visibility is seriously reduced, which is defined as driving rain, snow or fog with visibility less than 100 metres. Fog lights cause dazzle to other drivers and can attract a £30 non endorsable Fixed Penalty Notice.

Other lights – It is an offence to show a red light to the front of a vehicle (including a reflector) and a white light to the rear unless reversing.

Once again these offences are dealt with by means of a £30 non endorsable Fixed Penalty Notice.

It does not matter if the lights are mounted inside or outside the vehicle, just that the light can be seen from the outside. This could also include neon lights fitted under or on the side of a vehicle and red LED windscreen washer jets. Green lights can only be fitted on Medical Practitioners vehicles.

Number Plates:

Number plates must conform to current requirements in relation to size in terms of the number plate itself and the characters, spacing, format and font.

You must not misrepresent the characters either, for example by spacing them to make a word or name or by strategically placing fixing screw covers to alter any character. Fonts including italic, bold and shadow are all illegal.

Number plates must be white reflective to the front and yellow reflective to the rear and the characters have to be black.


The exception to this rule is if the vehicle (note:the legislation states vehicle not the number plate itself) is registered prior to December 31, 1972, in which case black and silver number plates can be fitted front and rear.

If the number plates on the vehicle do not comply with the above legislation this could result in a £30 non endorsable Fixed Penalty Notice being issued and/or the DVLA being notified of the offence.

Ultimately the DVLA can withdraw the number plate from the vehicle temporarily or permanently, even though you pay for them, the DVLA still own the plate, you are just given the privilege of displaying the mark on a vehicle.


Stretch tyres are becoming more popular as the craze from Europe hits the United Kingdom.

Fitting this type of tyre to your car is illegal and could adversely compromise the handling of your vehicle.

The fitting of this type of tyre contravenes the Type Approval of the vehicle and renders it not fit for purpose as well as potentially invalidating your insurance.

This could lead to a prosecution of dangerous condition of vehicle, namely Art 54 of the Road Traffic (NI) Order 1995 and is subject to a £60 Fixed Penalty Notice and three penalty points endorsed onto your driving licence or being reported to Court.