Lattix - the first and still the safest passive sign mast
Cheshire Case Study
Passive road safety is becoming an increasingly important element in the road environment and in pursuit of a reduction in its traffic accident levels Cheshire County Council has decided to use the new Lattix crash absorbent sign post on a number of roads in the county. Thess Ratcliff talks to Neil Theobald.
The turning point for Lattix came last September when the HA approved its use for the A43 Towcester by-pass.
The Ten-Year Transport Plan set out a clear strategy for reducing road accidents. By 2010 the Government aims to reduce the number of killed and seriously injured on Britain's roads by 40% compared to figures for 1994-1998. Annually around 3,500 people are killed in road accidents in the UK and 40,000 are seriously injured. The direct cost of road accidents involving deaths or injuries is thought to be in the region of £3 billion a year.
Passive road safety is becoming an increasingly important element to incorporate in the road environment and in pursuit of a reduction in its traffic accident levels Cheshire County Council has decided to use the new Lattix crash absorbent sign post on a number of roads in the county. Cheshire recorded an average of 57 fatal and 775 serious accidents over the period 1994 - 98. In order to meet Government targets these figures must be reduced to 35 and 465 respectively.
Juralco, the manufacturers of Lattix posts have created a new concept in signposts in an effort to minimise the damage caused when a vehicle crashes in to one. The benefit of using this type of sign post is that it is non-injurious to vehicle occupants,' explains Neil Theobald, Principal Engineer Traffic and Transportation at Cheshire County Council.
Lattix is an 'energy absorbing' post made from aluminium and is therefore extremely lightweight. It is fixed onto a base plate and, upon impact it will initially crumple before shearing, minimising the damage to the vehicle and its occupants. Equally, however, the masts are proved to be surprisingly sturdy - a road sign, in certain circumstances may need only one Lattix pole to keep it upright. Cheshire already have experience of a sign of 12m square, supported on one Lattix mast.
The new design is the only one that conforms to the new European norm. EN12767, approved last September as BS EN 12767, which sets down the preferred criteria for passive safety of support structures for road equipment. In addition to this the signposts offer a number of benefits.
'When the post is hit,' explains Neil Theobald, 'there is no need to lay new foundations as you would with a conventional sign, just a new base plate. This could save a day's work for the maintenance department. Aesthetics are also important when considering street furniture installation and, adds Neil Theobald, these posts are pleasing to the eye. 'On a more practical level, when at a junction for example, a driver is able to see movement or the colour of another vehicle through the lattice-weave aluminium. This could potentially help to prevent an ill- judged move at a crossroads.'
Naturally all these plus points come with a downside - the posts are considerably more expensive than conventional signs. However strategic sitings of the posts could provide significant savings. 'There are long term advantages with a Lattix post,' explains Neil Theobald. 'Depending on the location of the post, there might not be a need to install a crash barrier.' If the crash barrier is there to protect the vehicle from the post, rather than any other element of the roadside environment, then, with Lattix there is no longer a need for the crash barrier. more....