A LEEDS University expert has described special “bridges” built to help bats cross roads as a waste of money.
The bridges, costing £350,000, were designed to stop bats being killed on a dual carriageway in East Anglia but they were shunned by the animals.
There were six bridges built for crossing points on the A11 between Barton Mills in Suffolk and Thetford in Norfolk.
The major dual carriageway was shut for five nights so the build could take place to stop the bats from colliding with traffic.
The bridges were designed to guide them safely across the road by imitating the lines of hedgerows that they would follow.
But a study by Professor John Altringham showed the bats that do use the crossing - are flying dangerously low.
He added: “Unfortunately, poor design or poor connectivity to the bats’ own ‘flyways’ along streams, hedges and woodlands has meant that few attempts have been successful.
“Poor monitoring, or a complete absence of monitoring, has meant that this failure has gone undetected, and we have continued to build structures that don’t work.
“We should certainly stop building wire gantries. All those tested, in this and in our previous study were totally ineffective.”
Professor Altringham said he studied the design at many projects and it was a waste of public money.
He added he would have preferred a “green” alternative by using bridges planted with grass, shrubs and trees.
He said: “There may have been lots of bats crossing at these points in the past, but not now. Those that do cross fly too close to the ground.”