How good is ANPR?

[plasticpig]

Today I found out that the insurance for one of my cars isnt on the MID. A couple of weeks ago the police were out with their ANPR kit doing the insuarance / tax disc checks. They were there all weekend and I must have past them about 8 times in the car but I didnt get pulled. I was wondering if there was something inherent in the colour or design of the car that would mean that ANPR would have problems reading the plate.

[RaksP]

which car was it?

most police pull you over cos they dont like the look of you rather than if they can see/ have info you are doing something wrong!

[s2art]

Depends on the ANPR system. For instance the City of London 'ring of steel' is set up primarily to look out for 'interesting' cars, that is with particular Police markers held against them, examples being 'stolen' or 'possible terrorist link'.

[plasticpig]

RaksP said:

which car was it?

most police pull you over cos they dont like the look of you rather than if they can see/ have info you are doing something wrong!

The Scimitar on my profile pic.

[DucatiGary]

do you have black and silver plates on it now ?

if so, ANPR cant recognise these

also plastic cars + radar speed traps = no reading

I do miss my scimitar

[plasticpig]

DucatiGary said:

do you have black and silver plates on it now ?

if so, ANPR cant recognise these

also plastic cars + radar speed traps = no reading

I do miss my scimitar

No still got the same ones on. Next time I see an ANPR setup I will stop and ask them why they are not pulling me over

What happend to your Scimitar?

[Burgmeister]

DucatiGary said:

also plastic cars + radar speed traps = no reading

Why is this? intrigued i am

[bus_ter]

DucatiGary said:

also plastic cars + radar speed traps = no reading

That's not true. I have a plastic car (Smart Car), and Radar traps (such as Gatso's) work just fine! Also mobile speed dectors (usually laser now) are instruced to aim at your license plate.. which is usually plastic.

[s2art]

The Tuscan Rat said:

Burgmeister said:

DucatiGary said:

also plastic cars + radar speed traps = no reading

Why is this? intrigued i am

Me to...Never heard this before, never had lazer refuse to read, cos car is plastic !!!

Plastic doesnt reflect RADAR but does LASER. The signal RADAR gets from a fibreglass car is mainly from the engine block. A much smaller signal.

[imbecile]

s2art said:

The Tuscan Rat said:

Burgmeister said:

DucatiGary said:

also plastic cars + radar speed traps = no reading

Why is this? intrigued i am

Me to...Never heard this before, never had lazer refuse to read, cos car is plastic !!!

Plastic doesnt reflect RADAR but does LASER. The signal RADAR gets from a fibreglass car is mainly from the engine block. A much smaller signal.

If that is true... given say, a largeish 4 cylinder model without balancing rods, or anything else that vibrates to buggery, surely the reading would be effectively random?

[xxplod]

In a nutshell, ANPR is as good as the data quality from the systems feeding in to it. It can also depend whether or not they have a feed from local intel databases as to whether it will ping cars with warning markers etc...

[s2art]

imbecile said:

s2art said:

The Tuscan Rat said:

Burgmeister said:

DucatiGary said:

also plastic cars + radar speed traps = no reading

Why is this? intrigued i am

Me to...Never heard this before, never had lazer refuse to read, cos car is plastic !!!

Plastic doesnt reflect RADAR but does LASER. The signal RADAR gets from a fibreglass car is mainly from the engine block. A much smaller signal.

If that is true... given say, a largeish 4 cylinder model without balancing rods, or anything else that vibrates to buggery, surely the reading would be effectively random?

Dont think the vibration makes much difference.

[mikechandler]

Not all insurance details are logged on the MIDIS system (IIRC around 8% of private policies and a very large percentage of commercial vehicles are not). Although, under EU regulations it is now compulsary for commercial vehicles to be entered but this obviously will not happen othernight.

[DucatiGary]

bus_ter said:

DucatiGary said:

also plastic cars + radar speed traps = no reading

That's not true. I have a plastic car (Smart Car), and Radar traps (such as Gatso's) work just fine! Also mobile speed dectors (usually laser now) are instruced to aim at your license plate.. which is usually plastic.

we have a radar speed sign in the village, smiles if your below 30 but doesnt register when in my present plastic car or my previous plastic car

The Tuscan Rat said:

Burgmeister said:

DucatiGary said:

also plastic cars + radar speed traps = no reading

Why is this? intrigued i am

Me to...Never heard this before, never had lazer refuse to read, cos car is plastic !!!

live and learn max, live and learn.

[DucatiGary]

plasticpig said:

What happend to your Scimitar?

the highly tuned V8 beast now belongs to PHer "gingerninja"

really wish i didnt sell it now though, that car was legendary.

[chris_tivver]

Depends on the wavelength of the radar and the exact construction but Gary is right it may see through plastic/fibreglass. What does it then pick up?

• May pick up engine block (and get roughly the right reading)
• May, if its a doppler radar, pick up the top of wheels and thus get a reading 100% too high
• May pick up nothing because the signal on its 2 way path through plastic gets absorbed and attenuated too much

This is IMHO from working on military radars rather than speed devices but the laws of physics don't change

Laser on the other had will be unaffected by the material, although in theory could get confused by other design factors (but unlikely with cars)

[Brett928S2]

DucatiGary said:

do you have black and silver plates on it now ?

if so, ANPR cant recognise these

also plastic cars + radar speed traps = no reading

I do miss my scimitar

Hi

Hmm thats interesting....my Porsche is "mostly" aluminum and plastic front and rear PUs....

So am I speed trap invisible ???

All the best Brett

Edited by Brett928S2 on Wednesday 18th July 00:59

[s2art]

Brett928S2 said:

DucatiGary said:

do you have black and silver plates on it now ?

if so, ANPR cant recognise these

also plastic cars + radar speed traps = no reading

I do miss my scimitar

Hi

Hmm thats interesting....my Porsche is "mostly" aluminum and plastic front and rear PUs....

So am I speed trap invisible ???

All the best Brett

Edited by Brett928S2 on Wednesday 18th July 00:59

Unfortunately aluminium is a perfectly good reflector of radar. So no.

[planetdave]

How about 'square' stylee numberplates with two rows of characters? I've heard that ANPR and SPECS cannot read them. But that was down the pub and therefore not reliable.

[Brett928S2]

Hi

How about stick on front plates ?? Are they allowed and can ANPR read them ?

All the best Brett