Alcohol breathalysers are used by police officers throughout the world to enforce drink driving laws. They were first used by law enforcement in the USA (where the first breathalysers were invented) in the 1930's. They were introduced in the UK in 1967. In the UK all breathalysers used by the police MUST be type approved by the home office. Breathalysers can be used to:
- Carry out PBT's (preliminary breath tests)
- Carry out EBT's (evidential breath tests)
Preliminary Breath Testing
Preliminary breath testing is used for screening purposes and allows police officers to make a decision based on the result of the preliminary breath test as to whether or not a driver suspected of drink driving is arrested. The preliminary screening test is not intended to give a precise measure of a suspects alcohol levels, it is used to indicate whether their alcohol level is likely to exceed the maximum prescribed legal drink drive limit. Preliminary breath test readings are not used as admissible evidence to form the basis of any subsequent prosecutions in a court of law.
In the UK a police officer can insist on a driver providing a roadside breath test if he has reasonable cause to believe the driver has committed a traffic offence, has been involved in an accident or has consumed alcohol.
Preliminary breath testing machines are approximately the size (slightly bigger) of old fashioned mobile telephones. The mouthpieces are disposable and the whole process takes about a minute before the breathalyser produces a result.
Evidential Breath Testing
If a driver is arrested for a suspected alcohol related driving offence, he will usually be required to take an evidential breath test. Evidential breath testing machine readings ARE used as admissible evidence for the basis of a prosecution in a court of law.
Once a driver has been arrested he will be taken to the police station and will be required to undertake another breath test on an evidential breath testing machine. The driver will be required to provide two samples of breath. The lower of which will be used as evidence of the level of alcohol in the suspects system at the time of the alleged offence.
- If there is a significant difference between the two readings produced by the evidential breath testing machine, the results the machine produced will be deemed as unreliable and a blood or urine test will then be required.
- If the reading is below 35 µg and 39 µg/100 ml breath then the driver should be released with caution or without charge.
- If the reading lies between 40 µg and 50 µg/100 ml breath, the driver has the right to ask for a blood sample.
- If the reading is above 50 µg/100 ml breath then the driver will be charged with the relevant offence.
Breath Testing Outside of Law Enforcement
Breathalysers are not exclusively used by police officers. They are used by many professionals such as probation officers, correction officers, prison officers, doctors and nurses. Employers may also use breathalysers to test their employee's alcohol levels.
Breathalysers in the workplace are becoming increasingly common, especially in jobs where there is significant risk involved and safety is paramount.
Breathalysers are becoming increasingly common in the consumer market too. A personal breathalyser can allow parents to monitor their children's alcohol intake for instance, many people also use or would like to use a personal breathalyser to test their own alcohol levels to ensure they are below the relevant legal drink driving limits and can drive legally.
Breathalysers can be used to help prevent drink driving in more ways than one. Ignition interlock devices use a breathalyser to test if a motorist is over a prescribed limit. If he is over the limit, the car will not start!
Since the breathalyser was introduced the number of people convicted of drink driving has run into the millions.