Speed camera leeway in Canberra?

Rangi said :

Slightly off topic here, but does anyone know what the rules/laws, in regard to hi-vis clothing, are for police working on roads, i.e when pulling someone over?

Dunno about ACT, but in Dubbo just over 5 years ago the police pulled over an uncle who was speeding to some sort of accident cause he worked for work cover, and after trying to explain himself, he got a speeding ticket. So in response, he got out of his car and fined the copper for a range of breaches including not wearing the high vis, too even not pulling over far enough from the side of the road. Doubt you’d ever see that in the ACT though.

troll-sniffer said :

“But yer honour I was doing 87km/hr in the 80 zone because I had rung up and checked how fast I could get away with”.

I think you’ll find the tolerance levels are not able to be changed willy nilly. They do set these tolerance levels to allow for inaccuracies of the speedometers in people’s cars, and also for potential inaccuracies in their equipment, although I believe they do perform regular calibrations on their equipment.

If you think their camera is screwed, and you were most definitely not speeding, ask for a calibration certificate. Then get one for your vehicle too, and see them in court if things don’t add up.

Like I said, it was my first in about 15 years, and I was having a frantic day, and the road seemed like an eternity. No excuses though.

DavidL5N96 said :

Note that apart from your speedo the diameter of your tyres has an effect as the tread wears down – you are going faster with a smaller diameter – I will leave it to the experts to work out if this is important.

Yes, and as I’m an expert I should also add that this effect can be negated if you drive over too many ants as they tend to stick and cause much bigger diameter tyres.

Special G said :

Why is it people always seem to want to know – How much can I speed before I get booked? How about try not speeding for a change.

bingo! i get frustrated at this sort of comment [#6], given that the speed ‘limit’ is exactly that, an upper limit, not a prescription for exactly the speed at which drivers are supposed to travel: I get frustrated when people go at a speed 5-10 kmh less than allowed. why? those [like moi] who travel a few kays under the posted limit are probably exercising due caution and diligence. i recommend it to all drivers…

Might be the end of the story for you NeedHelp but it ain’t for the rest of us. They could change it overnight to a finer tolerance and as long as they can satisfy a learned member of the judiciary that they are not at risk of booking motorists doing the speed limit there are no comebacks. Imagine the scenario:

“But yer honour I was doing 87km/hr in the 80 zone because I had rung up and checked how fast I could get away with”.

Thoroughly Smashed said :

NeedHelp said :

The 10% is correct, but for obvious reasons, it’s not advertised. I went out of my way to find out when I was clocked at 88kph in an 80. The tolerance level was 87. Missed it by THAT much.

First and last ticket in about 15 years.

Being fined for 88 in an 80 zone doesn’t actually prove the threshold is 87.

I asked them about tolerance levels. They told me, that in my case, had I been clocked at 87, I would been spared a ticket. I have it in writing. End of story.

Slightly off topic here, but does anyone know what the rules/laws, in regard to hi-vis clothing, are for police working on roads, i.e when pulling someone over? In my industry any of our people working any where close to the road, carpark etc have to wear it, but i have recently seen 2 seperate people (no not me) pulled over with the police officer standing/working on the road in plain uniform.

And don’t even get me started on windsreen washers running in and out of traffic in dark clothing

If you make sure your speedo is reading no higher than the speed limit and you won’t have a problem. It a speed camera FFS – cruising 5-10km/h over in good conditions and taking a chance on the cops being around is one thing, but driving through a speed camera with your speedo reading over the limit is pretty stupid.

I usually set my cruise as close to the speed limit as I can (at least according to my speedo!), and I’ve never been booked driving past 100km/h speed cameras at 100km/h. Since there’s probably some error in my speedo and inaccuracy in my cruise control, there’s probably some margin for error from the camera as well.

The only ticket I’ve had from applying this principle was for doing 101km/h in an 80 zone that I thought was a 100 zone (the moral is that there’s less margin for human error!).

Welcome to Canberra, Jeckle!

Victoria has +3 km/h, or they did when I last lived there. There was a big fuss about it when it came in, because it had previously been +10%. So it went from 121 km/h in a 110 km/h zone to 113 km/h.

I have been led to believe that the 10% leeway was to account for errors in speedo reading and the police radar detection thingy.

I just try not to speed 🙂

Rawhide Kid No 2 said :

Officially None

quoted for the truth.

If it was 2km above, then people would drive 1-2km above the speed limit.

CanberraCreative said :

The problem is car speedos are deliberately conservative. Using a GPS speedo which gives a far more accurate speed, you’ll find most cars underestimate their speed by 5-8km/h.

I was using a GPS unit at the time, if you’re going to test theories out it has to be done right!!

TP 3000 said :

It’s 5k’s, so if you do 105k’s past the 100k speed camera’s you’ll be fine. However if you do 106k’s past the camera, you’ll get a fine for doing 6k’s over the speed limit.

I have tested the 105k theory on the Tuggeranong Parkway & I didn’t receive a notice.

The problem is car speedos are deliberately conservative. Using a GPS speedo which gives a far more accurate speed, you’ll find most cars underestimate their speed by 5-8km/h.

TP 3000 said :

It’s 5k’s, so if you do 105k’s past the 100k speed camera’s you’ll be fine. However if you do 106k’s past the camera, you’ll get a fine for doing 6k’s over the speed limit.

I have tested the 105k theory on the Tuggeranong Parkway & I didn’t receive a notice.

Because your speedo obviously under reads Einstein!

It’s 5k’s, so if you do 105k’s past the 100k speed camera’s you’ll be fine. However if you do 106k’s past the camera, you’ll get a fine for doing 6k’s over the speed limit.

I have tested the 105k theory on the Tuggeranong Parkway & I didn’t receive a notice.

Why is it people always seem to want to know – How much can I speed before I get booked? How about try not speeding for a change.

NeedHelp said :

The 10% is correct, but for obvious reasons, it’s not advertised. I went out of my way to find out when I was clocked at 88kph in an 80. The tolerance level was 87. Missed it by THAT much.

First and last ticket in about 15 years.

Being fined for 88 in an 80 zone doesn’t actually prove the threshold is 87.

I can speak from experience as I’ve recently moved here as well: if you’re going 68 in a 60, they will get you. It’s 1 pt. and ~$150.00. Apparently the cops here don’t excuse a “momentary lapse in judgement.” 😀 Oh well. Lesson learnt: don’t speed in Canberra.

The 10% is correct, but for obvious reasons, it’s not advertised. I went out of my way to find out when I was clocked at 88kph in an 80. The tolerance level was 87. Missed it by THAT much.

First and last ticket in about 15 years.

DavidL,

As a tyre wears, the diameter decreases. For each revolution of the drive train, as read by the speedometer, the vehicle travels a lesser distance.

The actual speed is increasingly lower than the indicated speed.

Australian Design Rules for speedometers in motor vehicles show the variation.

DavidL5N96 said :

Whilst we are on this topic, when are the police going to charge P platers who have the P plate on the front and not the rear (speed photos are of the rear of the car – and that makes me laugh when I see someone slow down before the camera and start speeding up when passing through)

Surely you don’t want P platers being sent to court for missing a P plate! A $99 infringement notice should be enough to teach them a lesson.

Speed camera vans are not used in road works zones, you will occasionally find the police will though patrol them.

Having said that, most speed camera vans are visible for quite a distance ahead, if you’re paying full attention to the road you normally have time to slow slightly if you’re like most people travelling slightly above the speed limit. If you’re travelling well above that’s when you will normally get caught.

Don’t know about the ACT but NSW was 10% plus 1 when I was involved in it a few years ago, I doubt if it would have changed.

10% was the allowed variable for speedometers to comply with Australian Design Rules, and I understand that was why that figure was used, i.e. some speedos can technically read 10% slow and still be within the specs of the ADR, this could mean that your speedo shows 60 when you are actually doing 66. So, the 10% plus 1 was used so that you should only get a ticket if your speedo is showing that you are speeding [assuming that it is within ADR specs].

One other thing to remember is that changing wheel size can have a big impact on the accuracy of your speedo.

deye is spot on – using the highway speed checks outside Melbourne and Albury over a period of time (and numerous checks), I had one car which read 94kph when doing 100, another car which read 105 when doing 100. Nowadays my GPS (which I treat as not being trustworthy) gives reasonable confirmation of my previous readings. Note that apart from your speedo the diameter of your tyres has an effect as the tread wears down – you are going faster with a smaller diameter – I will leave it to the experts to work out if this is important.

If you thought that the leeway is 10% you are going to get booked. There is some leeway but not much. Sigh, knowing more than most drivers what my real speed is I get frustrated when people go at a speed 5-10 kmh less than allowed.

Whilst we are on this topic, when are the police going to charge P platers who have the P plate on the front and not the rear (speed photos are of the rear of the car – and that makes me laugh when I see someone slow down before the camera and start speeding up when passing through)

I have heard from a fairly reliable source that the leeway in NSW for fixed cameras is 10% + 1. ACT probably has something similar, but don’t quote me on that.

Your best bet is to assume your speedo under-reads by 10%, and the speed camera over reads by 2km/h. Travel past them all at a few k’s under and you’ll be fine.

astrojax said :

why should there be a leeway?

because there is very little that is 100% accurate including your speedo and the cameras

What’s the leeway? I know, anecdotally, a few of the speed values that it isn’t – but that’s not answering your question.

As a newcomer to Canberra you’d be well advised, when considering your speed, not to take any cues from the road and surrounding environment, otherwise you may find yourself doing, for example, 110 in an 80 zone, or worse, 80 in a 60 zone.

You’d also be well advised to stick to roadwork speed limits not only because you will occasionally see police enforcing these, but because some of the roadworks are a bit tricky to negotiate and the route through the roadworks can change.

But there has to be some sort of leeway. There are so many variable factors affecting a car’s true speed that seemingly small factors like tyre wear and the inflation level of tyres can affect the speed by 2 to 3%.

why should there be a leeway? the posted limit s the maximum speed, in good conditions, at which you should drive on the stretch of road to which it applies – why should you want to do more?

Officially None