Swarkestone Bridge is an ancient monument just under a mile long and has 17 arches (six of which have been unaltered since medieval times). It has a weight limit of 7.5 tonnes, but vehicles frequently exceed this. A lorry driver was fined in 2016 after he ignored 8 warning signs before driving a 44 tonne lorry across the bridge.
A study by The RAC Foundation found that more than 3,000 bridges in the UK are not fit to support the heaviest lorries which can weigh up to 44 tonnes.
Together with partners Clearview Intelligence, an innovative scheme was developed that could warn approaching drivers of overweight vehicles to divert before reaching the bridge. It recognises differing weight limits by vehicle classification to encourage an overall reduction in traffic speed.
Vehicle Activated Hazard Warning Signs were installed to encourage weight limit compliance and change driver behaviour. Any class of vehicles exceeding the weight limit threshold are specifically targeted by ‘7.5t 210 Yards Ahead’ Warning Signs triggered by vehicle count and classification, which has been fine tuned to detect and allow buses across the bridge.
The two hazard warning sign sites have no mains power so they are both solar powered.
‘Even a short closure of the tunnel causes great congestion in the area, and if an over height vehicle were to cause that level of damage, the tunnel could be closed for hours, if not days, which would bring the whole of the South East of England to a standstill.
When the Coeval over height vehicle detectors were first installed, we were talking about 10’s of vehicles a day that we were stopping; we are now down to low single figures, 4 or 5 vehicles a day we need to extract for being over height, so it’s a great improvement in efficiency through the crossing.’
‘Having used Coeval for the first time, we found them to be friendly and really helpful in ensuring we received the correct item we required. We were happy with the extremely quick response times and professional service they offer. We would definitely recommend their services to others.’
‘Thank you for your prompt and efficient service regarding our request for training on the 21st of August. You guys have been incredibly helpful over this.’
‘Coeval won the tender for the replacement overheight vehicle detector systems. The work was completed within programme and budget. We are now satisfied that the new systems will help protect the bridges for several years to come.’
‘A sound, honest and efficient service provided by Coeval. Would be very happy for Coeval to manufacture and supply more of Swindon’s signs.’