Variable Speed limit Dublin Port Tunnel

madmac187

Hi everyone, I use the Port Tunnel quite a bit, I’m wondering does the speed camera speed limit change with the signs when gone down to 50kph from 80kph. I went through it this evening no traffic and half way realised it was 50 instead of 80 wondering am I going to get done is all. Lots of trucks go through and ignore it and just wondering if it changes. Any and all help is appreciated.

GM228

The ASC system is calibrated for 80 km/h only in the tunnel, it does not change when the variable limit is introduced.

H3llR4iser

50 kph in the tunnel is actually a ridiculous limit - if there's any "danger" (which there isn't, it's probably one if not the most up-to-modern-standards stretch of road in Ireland), you'd want vehicles to clear the enclosed space quickly, not keep them in it for longer.

CrankyHaus

H3llR4iser wrote: »

50 kph in the tunnel is actually a ridiculous limit - if there's any "danger" (which there isn't, it's probably one if not the most up-to-modern-standards stretch of road in Ireland), you'd want vehicles to clear the enclosed space quickly, not keep them in it for longer.

Isn't it to prevent people emerging from the tunnel at 80 km/h to be faced with a tailback at the toll plaza? Seems reasonable to me.

magicbastarder

yeah, surely it's imposed due to congestion, not as a reaction to a dangerous situation?

ted1

H3llR4iser wrote: »

50 kph in the tunnel is actually a ridiculous limit - if there's any "danger" (which there isn't, it's probably one if not the most up-to-modern-standards stretch of road in Ireland), you'd want vehicles to clear the enclosed space quickly, not keep them in it for longer.

Traffic flows better at 50. And avoids bottlenecks at the end.

H3llR4iser

magicbastarder wrote: »

yeah, surely it's imposed due to congestion, not as a reaction to a dangerous situation?

Yeah what I thought, but there's this:

madmac187 wrote: »

... no traffic and half way realised it was 50...

Probably somebody forgot to flip the value back?

CrankyHaus

H3llR4iser wrote: »

Yeah what I thought, but there's this:






Probably somebody forgot to flip the value back?

Bottlenecking at the southbound toll plaza can be a bit strange and short lived. I was there last week and the barriers were shut for 5 minutes or so for no apparent reason. Big tailback coming up out of the tunnel and it was a bit hairy for some drivers to drop from 80 km/h to stopped if they weren't paying much attention. I wasn't the only one putting on my hazard lights to warn drivers behind me. After a few minutes the barriers started working again and it all cleared quickly.



I can imagine 50km/h being a valid congestion control and safety measure in that circumstance and by the time you reach the toll plaza the tailback could be gone.


Worth noting that some Brexit related adjustments are underway around the boundary of Dublin Port at the mo too. Apparently this includes some planned restrictions of Bond Street access to Eastpoint Business Park from the port tunnel and may include some traffic control exercises on the tunnel itself.

cdaly_

madmac187 wrote: »

I went through it this evening no traffic and half way realised it was 50 instead of 80

H3llR4iser wrote: »

Probably somebody forgot to flip the value back?

Or possibly the traffic was flowing freely because of the 50 speed limit?

markpb

H3llR4iser wrote: »

50 kph in the tunnel is actually a ridiculous limit - if there's any "danger" (which there isn't, it's probably one if not the most up-to-modern-standards stretch of road in Ireland), you'd want vehicles to clear the enclosed space quickly, not keep them in it for longer.

Isn't it possible that the people being paid to operate the tunnel, with access to all the data about how the tunnel operates and with all the information about each event are just slightly better placed to make a decision about the speed limit than you?

GM228

The 50km/h in the tunnel is only a lawful speed limit when there is an incident or maintenance works causing an obstruction or when there is a risk of congestion on the roads.

cdaly_

GM228 wrote: »

The 50km/h in the tunnel is only a lawful speed limit when there is an incident or maintenance works causing an obstruction or when there is a risk of congestion on the roads.

So pretty much all the time so?

Victor

H3llR4iser wrote: »

50 kph in the tunnel is actually a ridiculous limit - if there's any "danger" (which there isn't, it's probably one if not the most up-to-modern-standards stretch of road in Ireland), you'd want vehicles to clear the enclosed space quickly, not keep them in it for longer.

What if the incident is in front of the vehicles?