Drinking and driving is increasingly socially unacceptable, but up to a point it remains legal.
And that's where the Alcosense Digital Breathalyser Litecomes in.
It's a pocket sized device that analyses your breath for alcohol levels, just like a police breathalyser. Exactly what the purpose of this device is and how it should be used is actually quite contentious.
But in simple terms it gives you a reading that relates to the metrics used in the UK to police driving when intoxicated with alcohol. You can then, in theory, judge whether you are legal to drive.
What the device doesn't do is tell you whether you are safe to drive or will continue to be so. More on that in a moment.
The Alcosense Digital Breathalyser Lite offers two key features that make it attractive on paper: re-usability and accuracy.
Both are at least in part facilitated by the disposable blow tubes which provide a controlled method to introduce breath samples to the sensor while minimising contamination.
The device also has a self-clean function that's claimed to extended the usable life and accuracy of the device.
Alcosense makes various claims regarding the accuracy of the sensor, the most specific of which is readings to within +/- 0.02 per cent of the BAC or Blood Alcohol Content. If true, that's probably even more accurate that you will ever need to know whether you are at risk of being over the limit.
It's worth noting a couple of things briefly at this point. Firstly, while the device gives readings in terms of BAC it's actually measuring alcohol content in your breath and inferring a BAC level.
That's what a police roadside breathalyser also does. Should you be breathalysed at the road side and fail the test, you'll be taken to a police station for further breath tests on a more accurate calibrated machine. You can't be convicted purely on the evidence of a roadside breath test.
For the record, the UK limit is currently set at 80mg of alcohol per 100ml of blood. It varies around the world, but the UK limit actually allows for a fairly significant level of intoxication.
Most European countries operate a 50mg limit. Others, including Czech Republic, operate a zero-tolerance policy. Any level of detected blood alcohol is illegal.
The procedure for using the Alcosense Digital Breathalyser Lite is very straight forward. Simply plug in a blow tube, power it up. You'll then be given a count down timer before the 'BLOW' indicator gives you the go ahead.
Then blow into the the device until an audible beep tells you to stop. And pretty much immediately thereafter you'll get a reading.
At which point the critical question of accuracy enters the picture. Unfortunately, despite repeated requests to Avon and Somerset Constabulary in Bath, we weren't able to test the Alcosense Digital Breathalyser Lite against the devices used by the police.
In practice, what matters isn't how accurate the device is, but how its readings compare with those used by the police. On that subject, we cannot comment.
However, putting life and limb on the line, your erstwhile TechRadar reporter duly endeavoured to become mildly intoxicated over a light lunch in order to put the Alcosense Digital Breathalyser Lite through its paces.
Anecdotally, the readings were certainly consistent when performing multiple breath tests. They also were broadly in line with expectations derived from rule-of-thumb assumptions regards drinking and blood alcohol levels.
Overall, there are two conundrums facing the Alcosense Digital Breathalyser Lite. Firstly, is it accurate?
On that subject we can't be sure thanks to the disappointing lack of co-operation from Avon and Somerset Constabulary. That said, we've seen enough to think the device works well and would function in its intended role.
In other words, we think the Alcosense Digital Breathalyser Lite will indeed give you a good guide as to whether you are risking driving over the allowed limit.
Whether that's actually a good idea and how useful that is will depend on your viewpoint. Most sensible adults will, for instance, know how much they've drunk over the course of an evening and have a reasonable idea whether it's left them fit to drive according to the law.
Where things get more complicated is the morning after. The speed with which alcohol is absorbed and processed varies significantly from person to person. Moreover, if you have been drinking during an evening with no intention of driving, you may not have kept track of your consumption.
You're then left with the very real prospect of still being over the limit the morning after. Inevitably, the government warnings relating to this risk tend to express the worst case scenario regards the likelihood of this happening. But it remains a very real problem and the very problem for which Alcosense chiefly promotes this device.
Whatever, having this gadget on hand will certainly give you a quick sense check the morning after should you be in any doubt. Even if it's not as accurate as the maker claims, we're confident it's good enough to tell you if you are over the limit.
Of course, against all that is the argument that whatever the legal limit, morally you shouldn't be driving if you have any alcohol in your blood. If you subscribe to that view, the Alcosense Digital Breathalyser Lite clearly isn't for you. For everyone else, it's a useful and affordable tool so long as you understand the limitations involved.