Taxi plates - could any drivers here tell me how much your MPG is affected by it?

samsemtex

Hi, could any drivers here let me know how badly having an Irish taxi plate on your roof affects your mpg. I had my brothers roof rails on my car the other day and my mpg plummeted. Just wondering what way taxi signs affect it here as they are huge compare to other countries.

Victor

I don't think its very straightforward as a lot of taxi work is stop-start and/or at a mix of low and medium speeds which throws things off completely.

L1011

Victor wrote: »

I don't think its very straightforward as a lot of taxi work is stop-start and/or at a mix of low and medium speeds which throws things off completely.

And indeed the exact shape/position of the taxi sign would have an impact, as well as the original MPG of the car. Theres no way someone can provide a "it has an X mpg impact" style figure.

Roof rails themselves vary wildly, the longitudinal rails on a Fiat Panda (fitted by default in Ireland) have an imperceptible impact and the Fiat branded latitudinal ones unladen only knock about 2% off; but big blocky third party ones are like sticking a brick on the roof for aerodynamics.

samsemtex

Yeah, i know but i suppose i was just looking for a rough figure. All taxi plates in Ireland are basically the same so they should be able to give me a rough idea. They are the most unaerodynamic looking things i have ever seen. They must be incredibly inefficient.

amacachi

samsemtex wrote: »

Yeah, i know but i suppose i was just looking for a rough figure. All taxi plates in Ireland are basically the same so they should be able to give me a rough idea. They are the most unaerodynamic looking things i have ever seen. They must be incredibly inefficient.

Rough figure? up 10%. Under 50kph aerodynamics aren't very important, so for daytime driving around a city it'll have very little effect.

Ham'nd'egger

Victor wrote: »

I don't think its very straightforward as a lot of taxi work is stop-start and/or at a mix of low and medium speeds which throws things off completely.

It still didn't stop the Regulator spending about €60,000 sending over two taxis to a wind tunnel in England to research the fuel drag caused by the position of a roof sign the other year.

Poly

Hamndegger wrote: »

It still didn't stop the Regulator spending about €60,000 sending over two taxis to a wind tunnel in England to research the fuel drag caused by the position of a roof sign the other year.

They could have built a wind tunnel for that!

foggy_lad

Hamndegger wrote: »

It still didn't stop the Regulator spending about €60,000 sending over two taxis to a wind tunnel in England to research the fuel drag caused by the position of a roof sign the other year.

thats cheap enough if they were on the meter!

samsemtex

amacachi wrote: »

Rough figure? up 10%. Under 50kph aerodynamics aren't very important, so for daytime driving around a city it'll have very little effect.

10%? Thats a substantial amount. Say a taxi driver spends €10,000 on fuel a year, thats €1000 which is a quite a lot. Im amazed no one has ever designed a more aerodynamic taxi sign in this country. No where else in the world are they like they are here.

Ham'nd'egger

Poly wrote: »

They could have built a wind tunnel for that!

They'd supply the wind (Hot air, no less) via a pipe from Kildare Street:D

Spook_ie

It's been suggested to the T.R and though not rejected out of hand I wouldn't hold your breath waiting for a change to anything remotely aerodynamic in the legislation. However that isn't to say a perspex cover angled downwards attached with something as simple as velcro wouldn't improve it or even a perspex box with aerodynamic styling and the all imprtant licensing details on a flat surface at the rear with integral illumination wouldn't go amiss. I've already thought about the loss in fuel consumption but the tooling efforts negate any one off projects at this time

amacachi

samsemtex wrote: »

10%? Thats a substantial amount. Say a taxi driver spends €10,000 on fuel a year, thats €1000 which is a quite a lot. Im amazed no one has ever designed a more aerodynamic taxi sign in this country. No where else in the world are they like they are here.

Up to 10%, if most of the time is spent at over 70kph, which they dont.

Wibbler

Hamndegger wrote: »

It still didn't stop the Regulator spending about €60,000 sending over two taxis to a wind tunnel in England to research the fuel drag caused by the position of a roof sign the other year.

Could they not just have sent the signs? They have cars in England, too.

Cookie_Monster

could you not just turn the signs lengthways to reduce profile?

samsemtex

Cookie_Monster wrote: »

could you not just turn the signs lengthways to reduce profile?

That is an interesting proposition. I wonder do the regs require that its mounted sideways. Keeping it in that position may also be a problem.

Alun

Wibbler wrote: »

Could they not just have sent the signs? They have cars in England, too.

I doubt it cost €60k to actually send the taxis, but that that was the fee charged for the wind tunnel use. In fact I'd imagine it was probably just as cheap to pop the two taxis on the ferry and pay for the petrol than to send the signs by courier.

And to a previous poster who suggested you'd be able to build one for that, you wouldn't get much of a wind tunnel for €60k ... McLaren's is rumoured to have cost £300 million!

Cookie_Monster

samsemtex wrote: »

That is an interesting proposition. I wonder do the regs require that its mounted sideways. Keeping it in that position may also be a problem.

roof rack bars crossways to mount it to. I'm sure they would produce less drag then the widthways sign would. Or even suction directly the the roof may be viable.


The real solution IMO is a specific paint scheme for all taxis in the country with a much smaller roof sign, less than 1ft wide like most countries

Cookie_Monster

Alun wrote: »

McLaren's is rumoured to have cost £300 million!

Well we all know how truthful McLaren are these days
:rolleyes::p

samsemtex

the money and Ferrari plans were just resting in their account!

Ham'nd'egger

Cookie_Monster wrote: »

could you not just turn the signs lengthways to reduce profile?

Legally we can do this..... on a fare that will be longer than 30KM and with the permission of the passenger. :rolleyes: