20mph limits

[Linas.P]

14 hours ago, ROYT said:

The plan appears to be that private car ownership is to be phased out entirely, except for the 'very important' people and the very rich.

This is literally the only conclusion one can reach looking at the BEV proposals for 2030 and ban of ICEV. There is no infrastructure to charge cars, there are not enough lithium to make them, so the only way this can work - cars will cost like £200k+ and only rich, famous or important will be able to use them. Like in 1920s or soviet union. Normal people will have no way of buying them and nowhere to charge them.

As for pollution form cars, again I have argued quite a few times and it varies between years, but generally pollution from transportation is ~10%, private and light vehicles (so that includes commercial vans and taxis) - 2.4% (2.1% diesel, 0.3% petrol). So even if we replace all cars with BEV that is only 2.4% of pollution. But wait - BEVs still not 100% clean, they are about 30% cleaner, so... that is 0.8% of pollution and our government and ecomentalists are ready to cause havoc and turn the society to dystopian mess for 0.8%... 

2 hours ago, Marko89 said:

To be fair this is correct, to a point. 

 And that point is ~65-85MPH nowadays. Even at 90MPH one is way more efficient than at 20MPH. It really depends on each individual car, aerodynamics, gearing etc. But if I remember right the petrol was most efficient at ~30% load and relatively low RPM (say 2000), meaning one has to get to top gear and do quite high speed to load engine 30%. Diesels were most efficient at ~40% load and even lover RPM ~1100, so as long as diesel is mated with right gearbox, they can even go 100MPH provided car is aerodynamic. But even then UK already has lowest NSL in Europe and 70MPH is already "eco speed". So this argument about reducing speed limits to reduce emissions is only really relevant on German autobahn, and nowhere else in Europe.. or the world. Like yes it is true, that driving at 80MPH car will be more efficient that at 140MPH...

Now Obviously, I am not saying there should be 80MPH limit in local town centre, but as you said - speed reduction only works to certain point and in principle only applies to motorways. Anything below 60MPH is already suboptimal, so decision of speed reduction from 30 to 20MPH should never be based on pollution. This is misconception or wilful ignorance and in most cases I thin reduction to 20MPH increases the pollution. Again highly depends on the car, but there is no way to load-up engine to ~30%-40% at 20MPH and keeping low RPM, even silly new X-Trail with 1.2L engine can't manage that. Now for trucks - they do have like 16-20 gears, and if they are loaded then they can get 40% load on the engine at relatively low speeds, but even then 20MPH is too low. Probably 50-60MPH is where they are most efficient.  

[LenT]

19 hours ago, wharfhouse said:

I'll have a read of that - problem is always going to be proving it was a specific speed bump that did the damage I guess...

What you want to do, Phil, is find yourself a nice pothole that has been reported to the local Roads Authority.  They are obliged to repair specific potholes within a certain time of being reported.  Otherwise they can become liable for any damage caused.

When I had my car Detailed by a local chap, I was discussing the vulnerability of alloy wheels.  He said that he had had two alloys on his Porsche broken while encountering a reported - but unrepaired - pothole and for which he claimed compensation from the Local Authority.

[royoftherovers]

2 hours ago, LenT said:

What you want to do, Phil, is find yourself a nice pothole that has been reported to the local Roads Authority.  They are obliged to repair specific potholes within a certain time of being reported.  Otherwise they can become liable for any damage caused.

When I had my car Detailed by a local chap, I was discussing the vulnerability of alloy wheels.  He said that he had had two alloys on his Porsche broken while encountering a reported - but unrepaired - pothole and for which he claimed compensation from the Local Authority.

Was the Detailer successful with his claims Len ?

[LenT]

3 minutes ago, royoftherovers said:

Was the Detailer successful with his claims Len ?

So he said, John.  

[Linas.P]

1 hour ago, royoftherovers said:

Was the Detailer successful with his claims Len ?

The pot hole claims usually are not that difficult, but it is hard to prove speed hump damage unless you can prove they are clearly excessively high or if there are no signs warning about them. If there is pot hole over certain size (not exactly sure in UK, but generally more 10cm circumference or more than 10cm deep) and it is not marked then local authority is liable for the damage.  I have successfully made few claims abroad, but haven't had any damage in UK yet. I guess mostly because one can't even drive fast enough due to speed humps everywhere. Once it was pretty easy (just a tyre for 140 Euro), but second time I had to sue the equivalent of council, because I had to call recovery truck and council didn't want to pay for that and as well it was new Merc with 20" wheels and one wheel was 1500Euro (2 damaged). Basically the claim was like 6500 Euro and they said "yes sure we happy to replace 2 tyres and fix the wheels for 750Euro, but not 'excessive' claim for replacement wheels, recovery and storage"... well they ended-up paying everything + 800 Euro legal costs.

[Marko89]

21 hours ago, Linas.P said:

Now for trucks - they do have like 16-20 gears, and if they are loaded then they can get 40% load on the engine at relatively low speeds, but even then 20MPH is too low. Probably 50-60MPH is where they are most efficient.  

Scania spent a fair amount of time trying to convince customers to buy lower powered engines than they were used to. This was based around fuel economy and emissions due to the increased thermal load. Your average supermarket wagon is actually relatively light in the grand scheme of things so it was easy to convince the big fleet buyers. However, your smaller owners operators are very much like us. LED by the heart - Why buy the 1.0L Focus when you can have a 1.5 with some poke. 

You can show someone as many scenarios as your like as to why they should really go with a straight six 450hp engine over a V8 churning out 730hp, but if their heart is set on it and they get similar or slightly better MPG over their older model they'll always go with the V8. In some cases it is justifiable such as guys in the Highlands who need to make ferries so don't want to be held up by hill climbs, or people with fresh produce such as fish that has a very limited shelf life. But, the majority of the time it is bragging rights and the like the extra go rather than require it.  

[Linas.P]

5 hours ago, Marko89 said:

Scania spent a fair amount of time trying to convince customers to buy lower powered engines than they were used to. This was based around fuel economy and emissions due to the increased thermal load. Your average supermarket wagon is actually relatively light in the grand scheme of things so it was easy to convince the big fleet buyers. However, your smaller owners operators are very much like us. Led by the heart - Why buy the 1.0L Focus when you can have a 1.5 with some poke. 

You can show someone as many scenarios as your like as to why they should really go with a straight six 450hp engine over a V8 churning out 730hp, but if their heart is set on it and they get similar or slightly better MPG over their older model they'll always go with the V8. In some cases it is justifiable such as guys in the Highlands who need to make ferries so don't want to be held up by hill climbs, or people with fresh produce such as fish that has a very limited shelf life. But, the majority of the time it is bragging rights and the like the extra go rather than require it.  

I suspect that fuel efficiency is high-up in selection criteria for logistics companies, however fuel efficiency is not the same as pollution. In either case neither will be reduced going from 30 to 20MPH. As well undersized engines could be detrimental for economy when on the motorway and smaller is not always most efficient. 

[Marko89]

On 8/12/2022 at 3:02 PM, Linas.P said:

I suspect that fuel efficiency is high-up in selection criteria for logistics companies, however fuel efficiency is not the same as pollution. In either case neither will be reduced going from 30 to 20MPH. As well undersized engines could be detrimental for economy when on the motorway and smaller is not always most efficient. 

With diesel they go hand in hand, as the DPF, EGRs etc become caked in carbon the exhaust emissions will also rise whilst the fuel economy will drop. Effectively an EGR as the name suggests is already choking the engine with dirty air, the lower the quality and flow rate the harder the engine will need to work. Which is where the need to keep things hot is important, otherwise you drop into regen which will burn alot more fuel. 

I agree that downsizing isn't always the answer, you just need to look at the real world MPG of a Mazda 3 v a downsized + turbo offering from the competitors. The problem with the smaller engines is they require boost far more often.