Enquiry Number

SCTMS/032/Q004

Project Title

TVO4 Temporary Haul Route Crossings

Client

Buckingham Group Ltd

Location

Various Site Locations In South Staffordshire

Date / Time

Saturday 20th August 2005 / 08.00hrs-13.00hrs

General Findings

Please find some general points on all of the proposed crossing points. I have itemised them in greater detail further into this report.  There are six main points that I feel need attention with most of the proposed sites, taking into account the length of time that these haul routes are to be utilised for.

Point 1: Mandatory Speed Restriction
On all of the sites there is a lack of adequate signage.  The proposals, in most instances, requires the reduction of the mandatory speed limit of the road from the national speed limit to a 30mph temporary limit. This process is going to be achieve  by 2 mirrored P670 (30mph sign) 100m in advanced of the P7001 (men at work sign).   This, I presume, relies on the driver to change their driving style and speed from a de-restricted zone to a 30mph restricted zone immediately. This coupled with the 400m distance to the stop line, I feel is not an adequate distance given that the minimum distance for an emergency stop for a passenger car in the highway code is 73m.  This does not take into account the large number of HGVs on the public roads at some of the haul route crossing points. There does not seem any provision on the drawings for repeat signage to enforce the speed restriction.

Point 2: Advanced Signage
Standard signage on de-restricted roads requires advanced warning to be distance plated counting down to the hazard. The bare minimum I would design for this scheme is from 500m (P7001) then advance for the mandatory speed restriction 50m further towards the datum point.  There should also be repeated intervals signs describing the hazard. Depending on the site and traffic flows, the addition of P584 with supplementary plate P584.1 (Queues Likely) signs would also be beneficial.

Point 3: Geographical Locations
The geographical position of a large number of the sites in respect to sight lines could have been planned with a bit more thought to the travelling public instead of the needs of the contractors.

Point 4: Skid Resistance
The condition of the carriageway in the vicinity of most of the crossings is questionable.  Has anyone undertaken a skid resistance test or is the data available from Staffordshire County Council?

Point 5: Position of Traffic Signal Heads
The position of the secondary heads in the mirrored fashion is compliant with Chapter 8 but, from past experienced, it would be advisable to give consideration to adopting the criteria of the secondary head.  This would be directly across from the primary as this configuration is now more wildly used by contractors and more importantly understood by the travelling public as it matches most conventional traffic signals.

Point 6: Right Turning Vehicles
There seems to be no thought given to right turning vehicles. If we allow right turns into the sites then the traffic will stack up which could cause shunt accidents especially around the bends on most of these sites. 

Specific Sites

Netherstone Lane
This particular site is on a B classification road, again it suffers from the six main points. The road width is only 3.4m wide.  In the event of two vehicles being stopped at the same time to allow a piece of plant to cross the carriageway there would be a need for one vehicle to reverse to a point in the road where they could pass safely. Unfortunately in both directions this will require the vehicle to transverse towards blind bends particular to the North of the crossing. The solution to this problem would be achieved by widening the road temporary over a short distance around the crossing to allow the vehicles to pass safely.
The use of traffic signals at this location is, I understand, being debated. My thoughts on them are as follows. Even though the road is quiet, the visibility is very poor and if traffic signals are not installed it would have to be a manned site with the operative using a stop/stop board (P7031) to aid the unsighted plant driver out of the works area.  This would not only put at risk to the operative but the public vehicle approaching the works site would not be under control (i.e. stopped) and a collision between the works vehicle and the public vehicle or the operative could happen. With a bit of site clearance (overgrown vegetation) the site lines to a standard traffic signalled haul route could be greatly improved. This haul route under signal control would then allow for the safe crossing of the plant and could be run on a Vehicle actuated principle thus cutting down on the human error factor. With regards to the small crossing across the access road to the Brown Field Farm, I feel that sight lines for both the farm traffic and the plant operators is adequate to allow them merely to cross on a give and take system.