Encouraging head on collision?

The study of British and Irish roads - their construction, numbering, history, mapping, past and future official roads proposals and general roads musings.

There is a separate forum for Street Furniture (traffic lights, street lights, road signs etc).

Registered users get access to other forums including discussions about other forms of transport, driving, fantasy roads and wishlists, and roads quizzes.

Moderator: Site Management Team

Post Reply
ColinB
Member
Posts: 28
Joined: Mon Jan 28, 2019 14:51

Encouraging head on collision?

Post by ColinB » Thu Sep 23, 2021 14:21

I noticed this east of New Alresford where the B3047 passes under the Watercress Line. I assume they don't want traffic to drive on the opposite side of the road. But what are the parallel short dashed lines meant to indicate?

https://www.google.co.uk/maps/@51.08834 ... 384!8i8192

DB617
Member
Posts: 878
Joined: Mon Dec 25, 2017 00:51
Location: Bristol

Re: Encouraging head on collision?

Post by DB617 » Thu Sep 23, 2021 14:25

ColinB wrote:
Thu Sep 23, 2021 14:21
I noticed this east of New Alresford where the B3047 passes under the Watercress Line. I assume they don't want traffic to drive on the opposite side of the road. But what are the parallel short dashed lines meant to indicate?

https://www.google.co.uk/maps/@51.08834 ... 384!8i8192
I believe that's the path within which the specified height limit is correct. Vehicles close to that limit should follow the lines, and the bridge should probably be preceded by <!> Oncoming vehicles in middle of road. And as a Luton driver I should probably know that...

User avatar
JammyDodge
Member
Posts: 211
Joined: Sat Oct 13, 2018 13:17

Re: Encouraging head on collision?

Post by JammyDodge » Thu Sep 23, 2021 15:20

DB617 wrote:
Thu Sep 23, 2021 14:25
Vehicles close to that limit should follow the lines, and the bridge should probably be preceded by <!> Oncoming vehicles in middle of road.
They are a little further up the road from the bridge on either side
Designing Tomorrow, Around the Past

User avatar
JohnnyMo
Member
Posts: 5527
Joined: Wed Jun 04, 2003 13:56
Location: Letchworth, Herts, England

Re: Encouraging head on collision?

Post by JohnnyMo » Thu Sep 23, 2021 16:00

The bridge/road looks straight so why is the indicated path on a diagonal rather than in the middle
Johnny Mo

User avatar
Chris5156
Member
Posts: 14871
Joined: Thu Sep 06, 2001 21:50
Location: Hampshire
Contact:

Re: Encouraging head on collision?

Post by Chris5156 » Thu Sep 23, 2021 16:02

JohnnyMo wrote:
Thu Sep 23, 2021 16:00
The bridge/road looks straight so why is the indicated path on a diagonal rather than in the middle
It’s not as straight as it looks. If you compare the bridge wall on the left to the kerb line there is a slight skew.

User avatar
JohnnyMo
Member
Posts: 5527
Joined: Wed Jun 04, 2003 13:56
Location: Letchworth, Herts, England

Re: Encouraging head on collision?

Post by JohnnyMo » Thu Sep 23, 2021 16:04

Chris5156 wrote:
Thu Sep 23, 2021 16:02
JohnnyMo wrote:
Thu Sep 23, 2021 16:00
The bridge/road looks straight so why is the indicated path on a diagonal rather than in the middle
It’s not as straight as it looks. If you compare the bridge wall on the left to the kerb line there is a slight skew.
Yes just noticed that and was about to delete my post
Johnny Mo

User avatar
Bryn666
Member
Posts: 31684
Joined: Thu Jun 20, 2002 20:54

Re: Encouraging head on collision?

Post by Bryn666 » Thu Sep 23, 2021 16:34

I hope those guidance marks are not finished as there's no kicker arrow with HIGH VEHS, no lead out tapers... there's a diagram in TSM Ch 4 and 5 for this.
Bryn
Traffic/Road Safety Dogsbody and General Grumpy Now-a-Thirtysomething Man
She said life was like a motorway; dull, grey, and long.

Blog - https://showmeasign.online/

WHBM
Member
Posts: 8423
Joined: Thu Nov 30, 2006 18:01
Location: London

Re: Encouraging head on collision?

Post by WHBM » Thu Sep 23, 2021 17:13

Bryn666 wrote:
Thu Sep 23, 2021 16:34
I hope those guidance marks are not finished as there's no kicker arrow with HIGH VEHS, no lead out tapers... there's a diagram in TSM Ch 4 and 5 for this.
I thought so too - here's how to do it better

https://www.google.com/maps/@51.0885794 ... 312!8i6656

(I originally wrote "How to do it properly" but changed it as someone is bound to come along with a comment :) ).

User avatar
Bryn666
Member
Posts: 31684
Joined: Thu Jun 20, 2002 20:54

Re: Encouraging head on collision?

Post by Bryn666 » Thu Sep 23, 2021 19:32

WHBM wrote:
Thu Sep 23, 2021 17:13
Bryn666 wrote:
Thu Sep 23, 2021 16:34
I hope those guidance marks are not finished as there's no kicker arrow with HIGH VEHS, no lead out tapers... there's a diagram in TSM Ch 4 and 5 for this.
I thought so too - here's how to do it better

https://www.google.com/maps/@51.0885794 ... 312!8i6656

(I originally wrote "How to do it properly" but changed it as someone is bound to come along with a comment :) ).
That's actually pretty spot on as far as these things go. The real problem is making sure the path for high vehicles corresponds with the arch. You see some examples and just clench your teeth.
Bryn
Traffic/Road Safety Dogsbody and General Grumpy Now-a-Thirtysomething Man
She said life was like a motorway; dull, grey, and long.

Blog - https://showmeasign.online/

fras
Member
Posts: 2775
Joined: Tue Apr 10, 2012 18:34

Re: Encouraging head on collision?

Post by fras » Thu Sep 23, 2021 21:35

Basically the bridge and the road are skewiff. Not unusual with railway bridges built when the road traffic was horse-drawn.

avtur
Member
Posts: 3960
Joined: Wed Oct 28, 2009 16:51
Location: Haywards Heath

Re: Encouraging head on collision?

Post by avtur » Thu Sep 23, 2021 21:37

JammyDodge wrote:
Thu Sep 23, 2021 15:20
DB617 wrote:
Thu Sep 23, 2021 14:25
Vehicles close to that limit should follow the lines, and the bridge should probably be preceded by <!> Oncoming vehicles in middle of road.
They are a little further up the road from the bridge on either side
Hopefully drivers approaching will take note ...
15 6 warning.jpg

User avatar
Bfivethousand
Member
Posts: 1286
Joined: Thu Jun 30, 2005 22:16
Location: Derbyshire

Re: Encouraging head on collision?

Post by Bfivethousand » Thu Sep 23, 2021 21:46

Chris5156 wrote:
Thu Sep 23, 2021 16:02
JohnnyMo wrote:
Thu Sep 23, 2021 16:00
The bridge/road looks straight so why is the indicated path on a diagonal rather than in the middle
It’s not as straight as it looks. If you compare the bridge wall on the left to the kerb line there is a slight skew.
I assume once upon a time this was the A31 at which time it was far more critical to sign as high a headroom as it was possible to get away with.

It's now far more appropriate to sign a lower headroom with conventional guidelines parallel with the kerblines. There's a very convenient alternative route avoiding this bridge, therefore no reason not to knock three or four feet off the headroom if needs be.
Witham ain't a dancer
It's just south of Braintree

SteelCamel
Member
Posts: 193
Joined: Fri Mar 27, 2020 15:46

Re: Encouraging head on collision?

Post by SteelCamel » Thu Sep 23, 2021 22:28

Bfivethousand wrote:
Thu Sep 23, 2021 21:46
I assume once upon a time this was the A31 at which time it was far more critical to sign as high a headroom as it was possible to get away with.

It's now far more appropriate to sign a lower headroom with conventional guidelines parallel with the kerblines. There's a very convenient alternative route avoiding this bridge, therefore no reason not to knock three or four feet off the headroom if needs be.
I don't see a "very convenient alternative route" - there's an arch bridge over the other end of the B3047 too (even though there's no railway on it), and none of the other roads have a connection to the A31. The B3046 also has an arch bridge. Sun Lane actually goes over the railway, and you can get to it from the A31 down Whitehill Lane, but that's very narrow and doesn't really look suitable for HGVs.

User avatar
Bfivethousand
Member
Posts: 1286
Joined: Thu Jun 30, 2005 22:16
Location: Derbyshire

Re: Encouraging head on collision?

Post by Bfivethousand » Thu Sep 23, 2021 23:10

SteelCamel wrote:
Thu Sep 23, 2021 22:28
Bfivethousand wrote:
Thu Sep 23, 2021 21:46
I assume once upon a time this was the A31 at which time it was far more critical to sign as high a headroom as it was possible to get away with.

It's now far more appropriate to sign a lower headroom with conventional guidelines parallel with the kerblines. There's a very convenient alternative route avoiding this bridge, therefore no reason not to knock three or four feet off the headroom if needs be.
I don't see a "very convenient alternative route" - there's an arch bridge over the other end of the B3047 too (even though there's no railway on it), and none of the other roads have a connection to the A31. The B3046 also has an arch bridge. Sun Lane actually goes over the railway, and you can get to it from the A31 down Whitehill Lane, but that's very narrow and doesn't really look suitable for HGVs.
The bridge over the B3047 to the west of the town centre has no signed headroom restriction coming in from the A31 although in the other direction it's signed (poorly) with a clearance of 4.8m (metric only :thumbsdown: ) reflecting the elevation of the arch over the nearside kerb in that direction. No guidance markings either. Bar that, it appears clear that anything below 5.03m / 16ft 6in can get under that bridge albeit with a little care westbound.
Witham ain't a dancer
It's just south of Braintree

DB617
Member
Posts: 878
Joined: Mon Dec 25, 2017 00:51
Location: Bristol

Re: Encouraging head on collision?

Post by DB617 » Fri Sep 24, 2021 12:24

avtur wrote:
Thu Sep 23, 2021 21:37
JammyDodge wrote:
Thu Sep 23, 2021 15:20
DB617 wrote:
Thu Sep 23, 2021 14:25
Vehicles close to that limit should follow the lines, and the bridge should probably be preceded by <!> Oncoming vehicles in middle of road.
They are a little further up the road from the bridge on either side
Hopefully drivers approaching will take note ...
Something I pray every time I move into the middle, especially with the many weird bridge/road interfaces where they are preceded by blind bends.

Post Reply