Cannabis & Driving

Author
Discussion

cashmax

Original Poster:

1,200 posts

246 months

Thursday 19th October 2023
quotequote all
My 17 year old son has just started driving (test booked but not taken yet) and I'm currently letting him drive everywhere for practice.

I know that when he is out with his mates at the weekend, there is a chance he might smoke cannabis and I have heard horror stories of people being over the limit and banned for drug driving on a Wednesday after smoking a joint on the Saturday. There seems to be all sorts of various information that seems to suggest anywhere between 24 hours and a week as a safe amount of time before driving.

Just wondered if anyone was willing to share any real world experience of this?

juice

8,808 posts

288 months

Thursday 19th October 2023
quotequote all
Unless he is doing something to attract the attention of the Police (speeding/weaving/DWDC etc) then unless he's actively smoking a spliff in the car then I'd say it was very unlikely. Just my take on it.

Dynion Araf Uchaf

4,647 posts

229 months

Thursday 19th October 2023
quotequote all
if your son is smoking cannabis, and then potentially driving whilst under the influence can I suggest you buy him a bus pass.

bitchstewie

54,871 posts

216 months

Thursday 19th October 2023
quotequote all
Dynion Araf Uchaf said:
if your son is smoking cannabis, and then potentially driving whilst under the influence can I suggest you buy him a bus pass.
I'm glad it's not just me thinking that.

Bloody remarkable.

LosingGrip

7,948 posts

165 months

Thursday 19th October 2023
quotequote all
cashmax said:
My 17 year old son has just started driving (test booked but not taken yet) and I'm currently letting him drive everywhere for practice.

I know that when he is out with his mates at the weekend, there is a chance he might smoke cannabis and I have heard horror stories of people being over the limit and banned for drug driving on a Wednesday after smoking a joint on the Saturday. There seems to be all sorts of various information that seems to suggest anywhere between 24 hours and a week as a safe amount of time before driving.

Just wondered if anyone was willing to share any real world experience of this?
Two offences when it comes to drug driving.

Driving whilst unfit through drugs. Think off their head. All over the road etc.
Driving whilst over the specified limit. Similar to alcohol there is a legal limit. For cannabis its 2.0. No idea in what units. And of course there is no way to messure how much one spliff would be as it depends on how much is in there, how strong it is etc. It also varies on how quickly it leaves the system.

I've drug wipped people who said they used it the day before and it was negative. I've had people say they smoked it two weeks ago and it was positive.

If its positive its arrested, trip to custody for a blood sample and then a waiting game. Blood results are taking months to come back (five-ish at the moment). If over the limit its a 12 month ban for the first offence minium.

I arrest more people for over the specified limit than unfit.

My advice is to make a decision. If he wants his driving licence, don't take the risk by smoking cannabis. I've had a few collisions were someone was involved in a fatal and tested positive for cannabis. They've now lost their licence.

Don Roque

18,063 posts

165 months

Thursday 19th October 2023
quotequote all
Hopefully he'll be caught soon, we don't need any more drug drivers than we already have.

DaiB

64 posts

22 months

Thursday 19th October 2023
quotequote all
Don't want to be overly judgemental towards the OP, he's not suggesting he should allow his son to drive high, he's asking when it is definitively safe for him to drive should he smoke a spliff or two at the weekend.

I suspect the numbers are all over the place as there is no legal limit for cannabis as there is for alcohol - so technically any trace found in his blood should he be involved in an incident would probably be enough for a drug driving charge. This could mean that well after any noticeable effects have worn off, there could still be a detectable amount of active substance sloshing around which could get him in trouble.

Conversely, because there's no legal position on it, there's no easily quantifiable data either. How strong is the stuff he's smoking? How much did he put in the joint? etc, etc.

Easy solution is zero tolerance on your part I would say. Any suspicion of smoking at the weekend, no driving that week. Or, even better, no driving at all until he learns you have to make sacrifices to be safe.

Once he has his own car and licence, regrettably he'll be able to do what he wants.

agtlaw

6,898 posts

212 months

Thursday 19th October 2023
quotequote all
LosingGrip said:
Two offences when it comes to drug driving.

Driving whilst unfit through drugs. Think off their head. All over the road etc.
Driving whilst over the specified limit. Similar to alcohol there is a legal limit. For cannabis its 2.0. No idea in what units. And of course there is no way to messure how much one spliff would be as it depends on how much is in there, how strong it is etc. It also varies on how quickly it leaves the system.

I've drug wipped people who said they used it the day before and it was negative. I've had people say they smoked it two weeks ago and it was positive.

If its positive its arrested, trip to custody for a blood sample and then a waiting game. Blood results are taking months to come back (five-ish at the moment). If over the limit its a 12 month ban for the first offence minium.

I arrest more people for over the specified limit than unfit.

My advice is to make a decision. If he wants his driving licence, don't take the risk by smoking cannabis. I've had a few collisions were someone was involved in a fatal and tested positive for cannabis. They've now lost their licence.
The correct procedure is arrest for unfit then charge with OPL. Police often get this wrong and the charge is amended at court.



Fermit

13,240 posts

106 months

Thursday 19th October 2023
quotequote all
A lot of people in their Ivory Towers on this subject.

AFAIK cannabis can stay in your system for up to 21 days. I don't know if how regularly or much you smoke has any baring on this. I'd imagine that's where the limits to gauge come in. Had a smoke at the weekend, driving on Weds, under said limit. Been round mates, sharing a bong, drive home afterwards, over. Just my guess.

I'd suggest being over the limit days later would be really unfair. I have very sporadically smoked weed, and whilst there is no way I'd drive the same evening, the day or days after I would see no problem.

oakdale

1,874 posts

208 months

Thursday 19th October 2023
quotequote all
Too big a risk imo.
An amusing thread about this subject below.
https://www.pistonheads.com/gassing/topic.asp?h=0&...

Grumbler

140 posts

114 months

Thursday 19th October 2023
quotequote all
My understanding is that when the limits were set the expert recommendation was 10.0.(ppm/litre?), broadly in-line with other European countries. However it was decided a ‘zero-tolerance’ limit of 2.0 would send a message. Information on time-limits until safe is understandably scarce due to difficulty in studying a prohibited substance but from what I can gather an occasional smoker with low tolerance (therefore light use) will generally pass a road-side test within 24hours whilst a regular, heavy smoker has a permanent background level that can take weeks to clear. But neither party would necessarily be cognitively impaired anymore than you would the day after a heavy drink.
Basically best to think about it as really draconian drink-drive limit. Essentiallly zero-tolerance.
As for the OP’s son…you just need to impress upon him that if he smokes (and he probably will at some point) no driving for couple of days. Just like you’d tell them not to drink-drive. Not worth the risk.

LosingGrip

7,948 posts

165 months

Thursday 19th October 2023
quotequote all
DaiB said:
Don't want to be overly judgemental towards the OP, he's not suggesting he should allow his son to drive high, he's asking when it is definitively safe for him to drive should he smoke a spliff or two at the weekend.

I suspect the numbers are all over the place as there is no legal limit for cannabis as there is for alcohol - so technically any trace found in his blood should he be involved in an incident would probably be enough for a drug driving charge. This could mean that well after any noticeable effects have worn off, there could still be a detectable amount of active substance sloshing around which could get him in trouble.

Conversely, because there's no legal position on it, there's no easily quantifiable data either. How strong is the stuff he's smoking? How much did he put in the joint? etc, etc.

Easy solution is zero tolerance on your part I would say. Any suspicion of smoking at the weekend, no driving that week. Or, even better, no driving at all until he learns you have to make sacrifices to be safe.

Once he has his own car and licence, regrettably he'll be able to do what he wants.
Yes there is. Have a look at Section 5A Road Traffic Act.


agtlaw said:
The correct procedure is arrest for unfit then charge with OPL. Police often get this wrong and the charge is amended at court.
Out of interest, why is this? I don't arrest for unfit unless there is evidence of someone being unfit (poor driving, poor results on a Field Impairment Test for example). I'll only arrest for OSL limit if there has been a positive drug wipe.

If I've arrested someone for unfit, when going through the MGDD/B I'll always say that they are under investigation for unfit and OSL.

Wacky Racer

38,919 posts

253 months

Thursday 19th October 2023
quotequote all

Nuttbelle

537 posts

16 months

Thursday 19th October 2023
quotequote all
Parents today, where is the discipline FFS

You don't smoke cannabis or
u don't go near the car !

Think twice b4 lying to me or u will never go near the car ever again

End of

RS_MAN_CHILD

284 posts

275 months

Thursday 19th October 2023
quotequote all
Don Roque said:
Hopefully he'll be caught soon, we don't need any more drug drivers than we already have.
This all the way if the parent(s) do not understand how appalling their judgement is to even allowing him to drive!!

agtlaw

6,898 posts

212 months

Thursday 19th October 2023
quotequote all
LosingGrip said:
Out of interest, why is this? I don't arrest for unfit unless there is evidence of someone being unfit (poor driving, poor results on a Field Impairment Test for example). I'll only arrest for OSL limit if there has been a positive drug wipe.

If I've arrested someone for unfit, when going through the MGDD/B I'll always say that they are under investigation for unfit and OSL.
The bar for unfit is lower. The driver can be unfit to drive through drink or drugs but below the statutory limit. You can arrest for unfit without doing a preliminary test; s.4(6)

Arrest for OPL is after preliminary test or failure to provide; see 6D







agtlaw

6,898 posts

212 months

Thursday 19th October 2023
quotequote all
DaiB said:
Don't want to be overly judgemental towards the OP, he's not suggesting he should allow his son to drive high, he's asking when it is definitively safe for him to drive should he smoke a spliff or two at the weekend.

I suspect the numbers are all over the place as there is no legal limit for cannabis as there is for alcohol - so technically any trace found in his blood should he be involved in an incident would probably be enough for a drug driving charge. This could mean that well after any noticeable effects have worn off, there could still be a detectable amount of active substance sloshing around which could get him in trouble.

Conversely, because there's no legal position on it, there's no easily quantifiable data either. How strong is the stuff he's smoking? How much did he put in the joint? etc, etc.

Easy solution is zero tolerance on your part I would say. Any suspicion of smoking at the weekend, no driving that week. Or, even better, no driving at all until he learns you have to make sacrifices to be safe.

Once he has his own car and licence, regrettably he'll be able to do what he wants.
Completely wrong.

Various drug driving limits have been in force since 2015.

In 2023, drug driving prosecutions exceed drink driving prosecutions.

https://www.gov.uk/government/collections/drug-dri...


Tony1963

5,282 posts

168 months

Thursday 19th October 2023
quotequote all
What often happens in practice, and how people often get caught, when a driver is impaired through drunk or drugs:

They know they’re near or over the limit, so, after making the decision to drive, they take care. Or so they think. They stay under the limit, don’t run red lights etc. but that takes a lot of their concentration, too much. And they just don’t see the other car, or the pedestrian, or the careless biker.

All drivers who chose to break the law with drink, drugs, speeding, dodgy tyres etc are relying on every other road user behaving impeccably, and as we all know, that’s NEVER the case.

Buy him a suitcase and tell him that if he is ever caught driving under the influence, he can put his belongings in it and gtf out of your house.

OutInTheShed

9,091 posts

32 months

Thursday 19th October 2023
quotequote all
When I was young, we gave up drinking at 16 so we could go places on mopeds.
By 18, we were back into pushbikes so we could go out for a drink.

HTHBIDI.

J6542

2,017 posts

50 months

Thursday 19th October 2023
quotequote all
Millions of people regularly smoke a joint at night and drive the next day, it’s no different to having a glass of wine after dinner and driving to work the next day.