Tuesday, 25 November 2008

Fault 2: No lane widening on the bend.

The original approved plans clearly show lane widening on the bend in line with the design requirements for a Local Distributor Road, see below.

'A carriageway width of 6.75 metres is required. Long straight roads which encourages higher traffic speeds and are visually monotonous, are not acceptable and a flowing alignment of curves is preferred with a minimum centre line radius of 60 metres. Lane widening is required on bends and if a bus router should be bus bays at every stop, designed in accordance with the recommendations in “Roads in Urban Areas”.'

The planned and approved lane widening has not been carried out.

Although Cheshire County Council charges for copies of their Design Aid many other County Councils provide free access on-line. North Lincolnshire is one such County Council. When you consider that all County Council Design Aids are derived from the same sources you will appreciate why County Council Design Aids are very similar.

For a similar road to Rookery Rise in North Lincolnshire the following standards would apply.

Carriageway Width .. .. .. .. 6.75 metres.
Carriageway widening .. .. .. .. Increased to 7.3 metres on bends of less than 75 metres centre line radius.
Horizontal alignment .. .. .. .. Minimum centre line radius 60 metres.

Footway width .. .. .. .. .. 2 metres.
Footway crossfall .. .. .. .. .. 2.5% (1 in 40)

Rookery Rise carriageway width is 6.75 metres and the bend in the vicinity of my property has a centre line radius of about 60 metres but the carriageway has not been widened to 7.3 metres on the bend as shown on the original approved plans.

Cheshire County Council's own published design aid states that road widening on the bend of the road in the vicinity of my property should be at least 0.75 metre. [0.75m is about 2 feet 6 inches.]

They also state that horizontal alignment shall be constructed to within plus or minus 13 mm of design and vertical alignment shall be constructed to within plus or minus 6mm. [13mm is about 1/2 an inch and 6mm is about 1/4 inch]

Cheshire County Council's Design Aid states that carriageway construction shall be designed in accordance with the principles laid down in the Highway Agency Standards; Design Manual for Road and Bridges Volumes 1 to 10.

Volume 6, Section 1, Part 1 TD 9/93 Highway Link Design includes information on carriageway widening.

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