ADUK Archive

Hello everyone.

It's been a while since I posted here (that's a great understatement).

Anyway, I have noticed that the southbound speed limit on the Blackwall Tunnel was reduced from 40mph to 30mph. In my opinion, the southbound tunnel doesn't have sharp bends and it was more than safe at 40mph (implying that it's still safe at 40mph ). The northbound tunnel's 30mph limit is in my view justified due to its narrow lanes and sharp bends.

Now, I would like to know your opinions about this (anyone who drives through the Blackwall Tunnel regularly / from time to time).

Also, the tidal flows have now ceased, which is a great relief to me, as I head from Tottenham to Chatham to get to University.

Well, the tidal flows were supposed to reduce congestion because in the morning rush hour(s) the London-bound traffic is crazy. So basically they came up with the ingenious idea to use one of the southbound tunnel's lanes and allow northbound traffic to go through it. Not hard to deduce however, that this seriously impeded the progress of the southbound traffic also as now only 1 lane was open to them (i.e. ME!).

The system couldn't be reversed in the evening, which was another problem with this system (they say due to the northbound tunnel being unsuitable for 2-way-traffic).

If anyone's interested, here's the article here: <clicky>

Your thoughts please.

Regards,
Jaabir.

I have used this tunnel very often during the last 10 years whilst driving a 26 tonne flatbed truck.
I found that 30, even when the limit was 40, was quite fast enough for me.
Tunnels are a potential for horrific RTCs with little or no direct access for emergency vehicles if one happens.
I can see the safety reasons for keeping the speed down as low as reasonably possible in a tunnel such as this.
Comparing this with the Dartford tunnel where more modern safety designs have been used, I can see why there is a speed limit difference in the two.
By the way, do you find the Blackwall tunnel a bit fumey as I was always glad to exit it and get some fresh air - well, as fresh as poss - it is London.

As for the using of using of lanes for tidal flow - good general idea but much greater potential for incidents.

Hello ROG, thank you very much for replying.

ROG wrote:I have used this tunnel very often during the last 10 years whilst driving a 26 tonne flatbed truck.
I found that 30, even when the limit was 40, was quite fast enough for me.

I can see where you're coming from. It's a shame the HGVs just inches from my bumper when I'm going through the southbound tunnel don't seem to agree. I have rarely seen an HGV sticking to the 30mph limit in there, and I have rarely come across an HGV that didn't show disapproval at having to stick to the 30mph limit (because they're behind me, ).

ROG wrote:Tunnels are a potential for horrific RTCs with little or no direct access for emergency vehicles if one happens.
I can see the safety reasons for keeping the speed down as low as reasonably possible in a tunnel such as this.
Comparing this with the Dartford tunnel where more modern safety designs have been used, I can see why there is a speed limit difference in the two.

Yes, it is unfortunte about the design of the tunnels, but IMHO 40mph is a sensible limit. Anyway, it's a shame that after exiting the tunnel the limit remains at 30mph for a considerable amount of time, at least this section could have remained at 40mph.

ROG wrote:By the way, do you find the Blackwall tunnel a bit fumey as I was always glad to exit it and get some fresh air - well, as fresh as poss - it is London.

Yes, definitely. I can't wait to get some comparatively fresher air (if you know what I mean), it gets so bad sometimes I switch on that air circulation thing while I'm in there.

ROG wrote:As for the using of using of lanes for tidal flow - good general idea but much greater potential for incidents.

Yes, good idea, but poorly executed.

I used to live in SE London and used the Tunnel quite frequently.

Yes I found it very fumey too, and noisy.

As for the ending of tidal flow the reason cited by Transport for London is saftey.

I read a string in another web site that says the danger occurs during the set up of the tidal flow and then again once the surge of tide traffic lessens.

When lane 2 of the southbound is closed, and controllers are waiting for the present traffic in that lane to clear, before unleashing northbound traffic up it, then some cars may stray into lane 2 not realising it's closed. Potential for a head-on.

Once the surge of north bound traffic starts getting gappy the same thing might happen.

In other words it seemed it was safer when there was lots of oncomming traffic, as then, it was obvious you shouldn't have been in that lane.

Whether the real reason for ending tidal flow is for saftey or just some crazy idea of the Mayor I don't know, but reading various Newpapers I don't think the controversy will ever be settled.

As for the speed limit of 30, there are times when it's OK to go quicker but many times when a lower speed is more appropriate like when it's packed with traffic and almost nose to tail and neck to neck. So as motorists were unable to choose their own safe speed they've had one forced on them! It's the same with 20mph limits outside schools.

Jack Russell wrote:It's the same with 20mph limits outside schools.

I like the "20 WHEN LIGHTS ARE FLASHING" limits as they make more sense.