How accurate are police breathalysers?
How accurate are police breathalysers?
Author
Discussion

Doppelkupplung

Original Poster:

185 posts

142 months

Sunday 11th December 2016
quotequote all
Lady from my office was driving home after having a couple of glasses of wine. She was sitting in traffic when someone t-boned her. Police were called and she was breathalysed and subsequently arrested for drunk driving. When she provided breath specimens they read 36 and 35.

Ive read elsewhere that the machines have 95% certainly levels, does anybody know this to be true?

DaveH23

3,355 posts

200 months

Sunday 11th December 2016
quotequote all
Doppelkupplung said:
Lady from my office was driving home after having a couple of glasses of wine. She was sitting in traffic when someone t-boned her. Police were called and she was breathalysed and subsequently arrested for drunk driving. When she provided breath specimens they read 36 and 35.

Ive read elsewhere that the machines have 95% certainly levels, does anybody know this to be true?
Said Lady is a fking idiot. Drink or drive never both.

To answer your question i'd say pretty accurate based on what I have seen and heard. Isn't the roadside test is just a guideline though. If they blow over at the roadside then they are taken in and the more accurate machine at the station is what is used as evidence.

Have seen many of the police camera action style programs of people just failing at the road side then just passing at the station and simply left to go after a stern talk.

WaferThinHam

1,680 posts

160 months

Sunday 11th December 2016
quotequote all
A quick google seems to be suggest that ones used by the police at the station are 0.03% accurate.

PorkInsider

6,622 posts

171 months

Sunday 11th December 2016
quotequote all
DaveH23 said:
Doppelkupplung said:
Lady from my office was driving home after having a couple of glasses of wine. She was sitting in traffic when someone t-boned her. Police were called and she was breathalysed and subsequently arrested for drunk driving. When she provided breath specimens they read 36 and 35.

Ive read elsewhere that the machines have 95% certainly levels, does anybody know this to be true?
Said Lady is a fking idiot. Drink or drive never both.

To answer your question i'd say pretty accurate based on what I have seen and heard. Isn't the roadside test is just a guideline though. If they blow over at the roadside then they are taken in and the more accurate machine at the station is what is used as evidence.

Have seen many of the police camera action style programs of people just failing at the road side then just passing at the station and simply left to go after a stern talk.
And from what I've seen of the police fly-on-the-wall programmes, they don't prosecute if the evidential tests are below 40.

I'm sure one of the PH BiB will confirm that (or not).

herewego

8,814 posts

243 months

Sunday 11th December 2016
quotequote all
Was she charged? I thought the lower of two tests was used and the limit was 35 with prosecution above 35 so she would be okay?

stupidbutkeen

1,025 posts

185 months

Sunday 11th December 2016
quotequote all
If she read 36 and 35 she should be ok, legal limit is 35 and police always take the lower of the 2 readings.

unless you are in scotland

And still a bit daft taking a risk after 2 glass's of wine when a taxi would be cheap enough. ( pay for 2 taxis and have 1 driver take her car home if its needed early next day, I have done that a few times myself rather than drive even after a single pint)

Doppelkupplung

Original Poster:

185 posts

142 months

Sunday 11th December 2016
quotequote all
DaveH23 said:
Said Lady is a fking idiot. Drink or drive never both.

To answer your question i'd say pretty accurate based on what I have seen and heard. Isn't the roadside test is just a guideline though. If they blow over at the roadside then they are taken in and the more accurate machine at the station is what is used as evidence.

Have seen many of the police camera action style programs of people just failing at the road side then just passing at the station and simply left to go after a stern talk.
Yes she behaved very irresponsibly and she has risked everything, if found guilty she's screwed...

The print out also had a couple of other numbers which I understand to be a zeroing of the machine before each sample was taken but I am not sure.

bitchstewie

67,983 posts

240 months

Sunday 11th December 2016
quotequote all
In all the cop shows I've watched the roadside test was only used to arrest you and get you the station to provide a specimen on the evidentiary machine where it's the lower of two "goes".

Doppelkupplung

Original Poster:

185 posts

142 months

Sunday 11th December 2016
quotequote all
Thanks for the replies.

She's on bail I so presume she has been. She has an interview in 10 days, is that the normal process?

xjay1337

15,966 posts

148 months

Sunday 11th December 2016
quotequote all
She's an idiot. Drinking and driving is my biggest pet peeve. I have lost someone very dear to me due to this. The kind of people who "just have a couple" and drive are the worst!

I appreciate this doesn't answer your question really.
From watching the TV, they usually take you back to the station for a blood test to confirm the roadside figures, I wasn't aware that the roadside reading only would

Either way, I would suggest she hire a lawyer.

cossy400

3,464 posts

214 months

Sunday 11th December 2016
quotequote all
bhstewie said:
In all the cop shows I've watched the roadside test was only used to arrest you and get you the station to provide a specimen on the evidentiary machine where it's the lower of two "goes".
This is how I understood the process to be.

Silly woman, but I fear here OP shes stretchin the truth with the figures.

WaferThinHam

1,680 posts

160 months

Sunday 11th December 2016
quotequote all
xjay1337 said:
She's an idiot. Drinking and driving is my biggest pet peeve. I have lost someone very dear to me due to this. The kind of people who "just have a couple" and drive are the worst!

I appreciate this doesn't answer your question really.
From watching the TV, they usually take you back to the station for a blood test to confirm the roadside figures, I wasn't aware that the roadside reading only would

Either way, I would suggest she hire a lawyer.
They won't take your bloods in the UK unless you can't or won't provide a sample of breath. Limit in the Uk is 35, so she would seem to be in the clear?

Seems like she's had a narrow escape.

e21Mark

17,616 posts

203 months

Sunday 11th December 2016
quotequote all
Bail doesn't mean she has been charged. I would guess that she is still in with a chance of escaping prosecution, given that the lower reading is 35? In fact, my money would go on her having an extremely lucky escape.

I don't think one should drive having consumed any alcohol.

xjay1337

15,966 posts

148 months

Sunday 11th December 2016
quotequote all
WaferThinHam said:
They won't take your bloods in the UK unless you can't or won't provide a sample of breath. Limit in the Uk is 35, so she would seem to be in the clear?

Seems like she's had a narrow escape.
Ah, I see, thanks for the clarification.

KevinCamaroSS

13,843 posts

310 months

Sunday 11th December 2016
quotequote all
e21Mark said:
Bail doesn't mean she has been charged.
I don't think you are correct with that statement. Bail applies after you have been charged, not before.

bigandclever

14,398 posts

268 months

Sunday 11th December 2016
quotequote all
From what I've read, on various motoring lawyer websites, charging is unlikely to go ahead with an EBM (Evidential Breath Machine) reading of 39µg% or lower because it has been shown that calibrated machines can over-estimate. But still... she's a knob.

Boosted LS1

21,200 posts

290 months

Sunday 11th December 2016
quotequote all
Don't they have a sobriety test in the States? I quite like that idea as opposed to a number.

Elroy Blue

8,841 posts

222 months

Sunday 11th December 2016
quotequote all
You only get prosecuted for 40+. If she blew 35 and 36 she won't be charged. The intoxilysers are very accurate, but the 40 prosecution level is used to avoid the 'it's not accurate' argument

Edited by Elroy Blue on Sunday 11th December 16:37

Elroy Blue

8,841 posts

222 months

Sunday 11th December 2016
quotequote all
Doppelkupplung said:
Thanks for the replies.

She's on bail I so presume she has been. She has an interview in 10 days, is that the normal process?
You don't get interviewed for drink driving. The blood option no longer exists either. It is only taken if she comes up with a valid medical reason as to why she can't provide an adequate, evidential breath sample.

(It's amazing how many drink drivers claim they've 'only had a couple')

agtlaw

7,410 posts

236 months

Sunday 11th December 2016
quotequote all
KevinCamaroSS said:
e21Mark said:
Bail doesn't mean she has been charged.
I don't think you are correct with that statement. Bail applies after you have been charged, not before.
Wrong. Mark is correct.

Evidential breath test machines are about 85% accurate.

In Northern Ireland, 17.5% is deducted from the lower specimen to obtain the result relied upon. In England, the lower result is relied upon.