Western Australia’s tougher breath-testing law took effect at midnight on 11 September 2019. It changed how a later evidentiary breath-analysis result is treated when determining a driver’s blood alcohol concentration (BAC) at the time of driving; it did not introduce random breath testing.
What changed under the 2019 law?
Before the reform, a driver’s BAC at the time of driving could be calculated from a later evidentiary breath-analysis result. The Road Traffic Amendment (Blood Alcohol Content) Bill 2019 removed that back-calculation. Under the change, the evidentiary reading became presumptive evidence of the driver’s BAC while driving. The change took effect from midnight on 11 September 2019, according to the Western Australian Government’s commencement announcement.
What does “what you blow is what you go” mean?
The phrase describes the shift away from estimating an earlier BAC from a later evidentiary test. The evidentiary breath-analysis reading is treated as presumptive of the BAC at the time of driving, rather than being adjusted down through back-calculation. It is a shorthand for the evidentiary rule, not a statement that every roadside screening result automatically determines a charge.
Is the presumption absolute?
No. The parliamentary explanation says the presumption is rebuttable. In appropriate circumstances, a person may seek to defend a charge with expert evidence based on blood analysis showing that their BAC at the time of the offence was lower than alleged. This is a general description, not advice about a particular case; anyone facing a charge should get legal advice about the evidence and applicable law.
#1 Best Overall
- Does not fulfill Court/DMV Ordered Ignition Interlock Requirements
- Selective BAC Alarm
- Accuracy: +/- 0.005% at 0.050% BAC
- Memory: Last 250 Tests
- Professional Installation Required
How is an initial roadside test different from evidentiary breath analysis?
A preliminary breath test is the roadside screening stage. The Road Traffic Act separately authorizes police to require a preliminary test in specified circumstances, including requiring a driver to stop for the test. The 2019 reform addressed how a later evidentiary breath-analysis reading is treated when considering BAC at the time of driving. It did not create the power to conduct random breath testing. The parliamentary explanation of the reform and the statutory source distinguish these stages: Bill explanatory memorandum and Road Traffic Act 1974.
Why did the government support the change?
The government said back-calculation could allow some drivers to avoid higher penalties or charges, and presented removing it as a way to address that problem. That was the government’s stated rationale, not a measured finding here about the reform’s effects. In its 11 September 2019 announcement, Acting Road Safety Commissioner Simon Grieve said: “Drink driving is a factor in one in five fatal crashes and one in ten serious injury crashes in WA.” The figure is attributed to a 2019 announcement and should not be read as a current crash rate.
Rank #2
- 【Conduct Daily Self-Checks Anytime, Anywhere】This compact and portable breathalyzer makes it easy to quickly check your alcohol level at home or on the go; it fits easily in your pocket, on a keychain, in your wallet, or in the glove compartment, making it ideal for outings, travel, camping, and parties.
- 【Convenient and Easy to Use】Built-in rechargeable design with convenient USB-C charging. Charge via USB-C/Type-C using your home adapter, car charger, or power bank—no need to frequently replace batteries.
- 【Bright Color LCD Display】Easy to read – With just a simple breath, the clear digital color screen lets you view results anytime, anywhere; simple one-button operation is beginner-friendly and requires no complicated setup.
- 【Accurate Semiconductor Sensor Detection】Compared to single-sensor breathalyzers, this device provides more precise blood alcohol concentration (BAC) readings with faster response times and higher accuracy.
- 【Important Note】 For more accurate readings, please wait approximately 15–20 minutes after eating, drinking, smoking, chewing gum, or rinsing your mouth; attach the mouthpiece and blow steadily until you’ve exhaled fully. Repeat the test after 2–3 minutes for comparison. Keep dry and avoid extreme temperatures. For personal reference only; not for legal or professional use.
What should drivers do?
If you plan to drink, arrange another way home before you go, such as a taxi, rideshare or sober driver. The government’s announcement advises people planning to drink to make other transport plans. A personal breathalyser reading should not be treated as permission to drive.
Quick Recap
Best Value
- 【Portable Contactless Breathalyzer】This breathalyzer adopts a safe and healthy non-contact test design, which ensures a fast, reliable and accurate test result without touching the device, so the test is hygienic- you don't need to use the blowpipe (the blowgun can cause bacteria)
- 【Fast and High-Precision Sensor】Breathalyzer has a professional airway design and a high-precision semiconductor sensor. Displays blood alcohol levels quickly and accurately. Then you can decide whether to drive after drinking.
- 【Easy to Use Breathalyzer】Please slide the switch down to turn on the breathalyzer. It will take 15 seconds to warm up, then the light will turn green and the breathalyzer will beep once to remind you to blow, then please blow for more than 5 seconds, the test result will be displayed on the LCD screen
- 【Automatic Alarm Function Breathalyzer Test】Green light for OK result(<0.02C), yellow light for caution result(0.02C-0.08C), red light for hazard result(≥0.08C).
- 【Portable & USB Rechargeable Alcohol Tester】The portable breathalyzer is small in size and can be put in your car, briefcase, or backpack. It comes with a USB cable that allows you to connect the breathalyzer to the USB port for quick charging
Rank #4
- [ALL-IN-ONE BREATHALYZER SET] This Portable Breathalyzer kit comes complete with a tester and power cord, providing everything needed for reliable level monitoring wherever you are.
- [EASY-TO-READ DISPLAY] The bright LED screen offers clear visibility of results in all lighting conditions, allowing for quick checks of your blood content with ease.
- [SAFETY SYSTEM] A built-in buzzer s users when they approach or exceed the legal BAC limit, promoting safe driving habits and reducing the risk of accidents.
- [BROAD MEASUREMENT CAPACITY] With a measurement range of 000 - 0.199C (0 - 1.9g/l), this breathalyzer ensures accurate readings for across various levels of consumption.
- [SIZING REMINDER] Always check your own size chart rather than relying on Amazon's size chart.
Rank #3
- [PURIFICATION TECHNOLOGY] Enjoy reliable measurements with our tester's advanced purification room that filters out impurities, accurate detection of only.
- [HIGH DEFINITION DISPLAY] The high definition color screen offers clear visibility of results, making it user-friendly in all environments and lighting conditions.
- [VISUAL SYSTEM] Features a three-color indicator light for straightforward interpretation of levels, eliminating guesswork in your readings.
- [AUDIBLE INTOXICATION ALARM] Stay informed with the audible intoxication alarm that alerts you when levels are unsafe, promoting responsible choices.
- [LONG LASTING RECHARGEABLE for battery] With its rechargeable for battery, this device is perfect for regular use without the hassle of constant recharging.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
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