30k speed limits for all urban areas on the way

https://www.boards.ie/discussion/comment/119898186#Comment_119898186

Which can have its impact on society reduced by a reduction in limits.

Arguments for 30k

• Safer routes for all users
• Less intimidating for cyclists and pedestrians
• Less pollution
• Greater chance of survival in the event of an impact
• Lower chance of life altering injuries
• Lower traffic noise

Arguments against 30k

• It's not fair!!11!

FishOnABike

https://www.boards.ie/discussion/comment/119898082#Comment_119898082

I can't see where that leap of reason came from.

The only claim I could see was that driving at 30km/h uses more fuel than driving at between 50km/h and 80km/h. This is evidently clear from the information in the link.

It does seem bizzare that we jump up and down about pollution and climate change but would bring in a blanket change that would increase emissions by almost a third in urban areas without carefully considering the justification on a case by case basis.

SeanW

Driving at 50kph saves fuel and reduces pollution vs 30kph. I've already shown this. It also saves people time. The collisions you refer to are largely theoretical in this country, and are not an issue for the vast majority. There may be other countries where your theoretical models are relevant to anything in practice, but not this one.

cnocbui

https://www.boards.ie/discussion/comment/119897742#Comment_119897742

Because going through a red light is the same as exceeding the speed limit. Your specious 'logic' is pretty twisted.

cnocbui

https://www.boards.ie/discussion/comment/119897960#Comment_119897960

Slower speeds cause congestion, because the throughput - bandwidth if you like - is reduced, meaning more cars on the road simultaneously than if speed limits were higher allowing a greater throughput.

Crashes increase when speed limits dip far below engineering recommendation

December 12, 2018

Speed limits set only five miles per hour below engineering recommendations produce a statistically significant decrease in total, fatal and injury crashes, and property-damage-only crashes, according to a group of researchers. https://www.sciencedaily.com/releases/2018/12/181212135021.htm

Seth Brundle

@SeanW - No. I'm saying that 30kph limits should only be applied sparingly and where the case for them is overwhelming. This can already be done with current rules.

So given there isn't an excessive amount of 30km/h zones currently and roads are designated with higher limits based on evidence etc, what makes you think roads won't be changed up from 30km/h under the new proposal? Why the opposition to this proposal to make sure it can be shown roads are designated appropriately based on evidence?

Alias G

https://www.boards.ie/discussion/comment/119897982#Comment_119897982

This link compares fuel consumption per 100km driven non stop. It does not imitate urban travel where a car is frequently brought to a halt at junctions, lights or in gridlock. This study does not inform us on fuel consumption in built up areas where the stop/start nature of travel will mean average speed is actually well below 30km/h in many cases. In this scenario strong acceleration followed by heavy braking will often result in higher fuel consumption. There is no 'punishment' to driving at 30km/h in urban areas when such an average speed is often unattainable anyway.

magicbastarder

beat me to it, i was just about to post that. the best speed for open-road efficiency is certainly not the same as the best speed for fuel efficient stop-start driving.

if you're driving between two sets of lights, probably the worst thing you could do for fuel efficiency would be to accelerate to 50km/h and immediately brake.

driving at 80km/h is more fuel efficient typically than driving at 50km/h, but you can bet your ass that trying to do that in moderate urban traffic would drive your fuel consumption up.

SeanW

https://www.boards.ie/discussion/comment/119898349#Comment_119898349

I'm old enough to remember Dublin City Councils "Love 30" consultation where they proposed to basically wallpaper almost everything with 30kph limits. I'd expect a 30kph as default nationwide to follow along similar lines.

https://www.boards.ie/discussion/comment/119898394#Comment_119898394

If your argument is valid, it would actually prove that speed limit reductions were not necessary, if people legitimately cannot get up to speeds faster than 30kph, then a higher limit is theoretical. However, a lot of 'urban' driving occurs on roads that aren't covered in traffic lights etc. and congestion is often not an issue outside peak times.

Alias G

https://www.boards.ie/discussion/comment/119898498#Comment_119898498

What are you on about. I referred to average speeds which are inhibited by the necessity to stop and junctions, lights and other traffic. Average speeds in Dublin are often between 10-20km/h because of this. No body say you can't reach 30km/h in your car. What a daft suggestion. What I did point out was the futility of driving at excessive speeds between sets of lights or junctions because it will not improve your average speed and cost you more in fuel.

magicbastarder

anyway, i'll just post my usual; at nearly 7pm on a sunday evening, the drive from the front gate of DCU to the front gate of UCD, a distance of 11.8km, google maps is calculating a time of 30 minutes. i.e. an average of less than 24km/h. and that's done nearly all on 50km/h roads (less than 1km of that on 30km/h roads, and more than 1km on 60km/h roads)

average speed attained is less than half the speed limit. yes, dropping the speed limit to 30km/h would lengthen the journey, but it's clear that as the majority of the journey is done at under 30km/h anyway, a lot of it simply stopped; it won't have nearly as much effect on journey times as people would claim.

Seth Brundle

@SeanW - I'm old enough to remember Dublin City Councils "Love 30" consultation where they proposed to basically wallpaper almost everything with 30kph limits. I'd expect a 30kph as default nationwide to follow along similar lines.

Ah so your opposition to this proposal is not based on anything other than fear and so you've made up your mind without even seeing any details of the proposal before they are even put forwards?

magicbastarder

this is the map from a few years back; i'm not sure how the plans have changed but the plan with DCC was making some of the remaining estates 30km/h, with the main roads remaining at 50.

https://www.dublincity.ie/sites/default/files/2022-09/30kp-speed-limit-review-2020_map.pdf

i did have an amusing conversation with a lad who lives on st. canice's road in glasnevin; he was giving out about the 30km/h limit. i said to him 'but sure there are big speed ramps on that road anyway, you can't do 50 regardless!' and his reaction was 'yeah, but people used to tear up and down that road so the ramps are needed'...

SeanW

https://www.boards.ie/discussion/comment/119898565#Comment_119898565

That may be true in Dublin City Centre, but it's not the same in every urban setting. Take for example the N59 into Galway City. If you want to go from where the 50kph zone starts to where the first traffic light is, it's 2km of straight driving. That's just one example.

Abbey View to Scoil Baile NuaS, N59, Co. Galway - Google Maps

https://www.boards.ie/discussion/comment/119898577#Comment_119898577

I consider it to be a template of what a 30kph as default would look like, yes. 30kph basically everywhere, with a few exceptions sparingly granted here and there.

magicbastarder

https://www.boards.ie/discussion/comment/119898653#Comment_119898653

it's an example which passes open farmland, so not exactly your typical urban road.

Furze99

https://www.boards.ie/discussion/comment/119896494#Comment_119896494

Are you suggesting then we could have varying speed limits for cyclists? One for those who say they are experienced and a lesser speed for the rest?

When it comes to speed limits, what's sauce for the goose is sauce for the gander. Be careful what you wish for.

Seth Brundle

https://www.boards.ie/discussion/comment/119900629#Comment_119900629

You really are getting ridiculous now.

as I previously posted:

how do you propose that anyone on a bike is aware of their current speed? Bear in mind that you also have to include bikes for 5 year olds in your reply. How would you propose to enforce speed limits for bikes? Would cyclists need licences (even 5 year olds)? Would bikes need reg plates? And now we're back to this feckin stupid concept put forward every so often by people who don't think things through properly!

magicbastarder

https://www.boards.ie/discussion/comment/119900629#Comment_119900629

speed limits are not required for bikes, for two main reasons; number 1, they are not motorised vehicles and do not have means to record their speed mandated. as Seth pointed out, would you be required to retrofit hundreds of thousands of bikes nationwide with speedos, and at what cost?

and the main reason: they're not required. the average cyclist would find it very difficult to sustain 30km/h. why force them to use a speedo to ensure they're not exceeding a speed they generally cannot reach?

looking for speed limits for bikes is trying to solve a problem that's not there.

AndrewJRenko

https://www.boards.ie/discussion/comment/119900629#Comment_119900629

Theoretically, I guess we possibly could, if that made any sense and if it made a significant contribution to reducing death and injury on the roads.

But it doesn’t make any sense and it wouldn’t make a significant contribution to reducing death and injury on the roads.

magicbastarder

it might not be intuitive for non-cyclists, but speed is not linear with effort; effort will generally square with speed above a certain speed.

according to various calculators, the effort to cycle at 30km/h is approx 50% higher than 25km/h. as mentioned you need to be quite fit to cycle above 30km/h (unless you have a decent enough tailwind).

the effort required to cycle at 35km/h, say, is double what it takes to cycle at 25.

https://www.omnicalculator.com/sports/cycling-wattage

Furze99

https://www.boards.ie/discussion/comment/119900791#Comment_119900791

You could have speed limits for cyclists both to protect them for their own good and for the safety of other users of public roads and public spaces. There are many/ most cyclists who toddle along at a moderate speed and are grand. You also have speed merchants on bikes who can be a menace.

magicbastarder

if it's such a good idea, i'm sure it's been done somewhere else in the world.

AndrewJRenko

https://www.boards.ie/discussion/comment/119902120#Comment_119902120

What impact would this have on current death and injury levels?

blanch152

https://www.boards.ie/discussion/comment/119900791#Comment_119900791

Electric bikes can hit 50kph, the same as cars can currently travel through urban areas. Being hit by one wouldn't be pleasant.

magicbastarder

If the bike can hit 50km/h while providing power, it's a moped. Someone on one of those is breaking multiple laws.

Unrealistic

https://www.boards.ie/discussion/comment/119903170#Comment_119903170

It's mad the people hate bicycles so much they have to make $h!t like this up.

Furze99

https://www.boards.ie/discussion/comment/119903616#Comment_119903616

Isn't it also a bit mad that some want 30kph speed limits for all urban areas but only seemingly for motorised traffic. I don't hate cyclists, it makes great sense as a way of getting around a city and that's all the transport I had growing up there. But regulations have to apply to all and arguably speed limits might be less for cyclists in some areas.

magicbastarder

there are some motorised bikes (very rare) that could hit 50km/h. but any bike providing assistance past 25km/h is legally a moped; and the rider subject the to usual laws around moped use (including tax/insurance etc.)

Ninap

Kinda pointless bringing in 30kph limit when there are lots of drivers - taxis included - doing 70-80 kph every night and early morning throughout the city. Check out the Rock Road, for example, with taxis whizzing down the bus lane and terrorising any cyclist that has the misfortune to be there

It would be nice if they would enforce the damn 50s before introducing more theoretical speed limits.

I regularly see cars doing 60-80 though urban streets, especially some of the more suburban ones or anything without a physical choke point.

We’ve councils that seem to think everything can be solved with signs and paint. We need enforcement. Most continental cities have local police enforcing things like traffic law.