The impact of potholes on our cars and pockets has never seemed more relevant than this year, with the economic damage in the UK estimated to be around £14.4bn in 2024. In a recent article by the BBC, Simon Williams from the RAC stated that

"Unfortunately, our roads are deteriorating, there's no question about that. This is really unacceptable, given the amount of money that drivers pay in motoring taxation; We estimate that to be around £45bn."

In the same article, Claire Holland from the Local Government Association (LGA) said councils, who are responsible for local road maintenance, had "limited resources" and a backlog of repairs costing some £16.3bn.

The previous Conservative government pledged to put an extra £8.3bn towards road maintenance in England over the coming decade and as part of that, £150m in additional funding for last year and this year has already been given to councils. Both the RAC and the LGA have called for the Labour government to commit to maintaining those spending plans, but even with such huge amounts of money, it doesn’t seem likely that we will see the back of potholes anytime soon.

If you hit a pothole with your car, there is a process by which you can try to claim compensation (insert an open can of worms here! —>), however, if you have a pothole outside your home causing you disturbance, where can you turn? It stands to reason that the impact of vehicles hitting a pothole outside your home may result in shock vibration travelling into the house and an increase in noise level, but what is the subsequent damage? Is this a mild irritation or could it be affecting your property?

Moniteye Investigates Residential Vibration Complaint

Moniteye recently visited a two-hundred year old cottage in Hampshire which was experiencing issues with vibration from the road surface outside. The residents of the cottage told us that, every time a heavy vehicle went past their house, the structure would shake and it was disturbing their sleep. We were also told that it was particularly bad when vehicles were on the carriageway furthest away from the house. Our brief was to demonstrate whether road traffic outside the property was causing vibration in the building, and to what extent it was affecting both the residents and the structure itself.

Unusually for this kind of investigation, the road outside the property had been repaired within the six months before our investigation, and it was this repair that seemed to have caused the issues within the cottage. Before the repairs to the road, the residents had experienced no vibration due to vehicles.

We proceeded to install two vibration monitoring devices, one at the ground-floor façade of the building facing the road, and one beneath the bed in the master bedroom where the vibration was disturbing their sleep. We then monitored the results over the course of one week, sampling every thirty seconds.

Assessing the Impact of Vibration

Typically when we are assessing the impacts of vibration we turn to British Standards BS 5228-2:2009, BS 7385-2 and BS ISO 4866:2010. These standards give guidance on the human and structural response to shock vibration in specific instances, generally pertaining to construction activities. The table below, reproduced from Table B.1 in BS 5228-2:2009, shows guidance on the human response to vibration.

*GUIDANCE ON EFFECTS OF VIBRATION LEVELS, REPRODUCED FROM TABLE B.1 BS 5228-2:2009*

Whilst BS 5228-2:2009 and BS ISO 4866:2010 go into great detail providing guidance on vibration measurement, data analysis and reporting, as well as building classification and guide values for building damage, the critical statement for this project comes from BS 7385-2 which notes that the probability of structural damage from shock vibration tends towards zero at 12.5 mm/s peak component particle velocity.

The ‘Design Manual for Roads and Bridges’ provides standards and advice pertaining to the design, assessment and operation of roads within the UK. LA111, a document within the Design Manual for Roads and Bridges pertains to the construction and amendment of highways. This document establishes that

‘the construction, operation and maintenance of highway projects can lead to changes in … vibration levels in the surrounding environment.’

It should be noted that operational vibration is scoped out of LA111 as ‘a maintained road surface will be free of irregularities as part of project design and under general maintenance, so operational vibration will not have the potential to lead to significant adverse effects.’ This implies that no operation roads should have significant adverse effects upon any sensitive receptors.

LA111 goes on to define the significance and the magnitude of construction vibration as shown in the tables below, where thresholds are defined by lowest observed adverse effect level (LOAEL) and significant observed adverse effect level (SOAEL).

*CONSTRUCTION VIBRATION LOEALS AND SOEALS FROM LA111*

*CONSTRUCTION VIBRATION LEVEL MAGNITUDE OF IMPACT FROM LA111*

Although there are no explicit criteria for existing roads in operation, the Design Manual for Roads and Bridges implies that if a receptor experiences vibration levels over 0.3mm/s, then this should be considered an adverse effect from the road and that said vibration should be mitigated against. Our survey results show that, over the period of one week, this threshold was exceeded at ground-floor level 252 times, and was likely to produce a minor adverse effect.

It should be noted again that this threshold is intended for the construction or repair of existing or new roads and is not intended to be a threshold for operation roads. Operational roads producing frequent minor adverse effects of this magnitude are likely to be far less tolerable to a receiver than roads undergoing temporary works.

These measured levels then appeared to be amplified through the building structure resulting in more significant vibrations within the master bedroom. Owing to the number of events recorded, it is not practical to show all of our measurement results here, but the following four events demonstrate the highest vibration levels measured at the external sensor during the night-time (23:00 hours to 07:00 hours), together with their resultant levels within the master bedroom. The use of these night-time levels means that it is less likely that vibration would have been caused by the residents themselves.

*DATE, TIME AND VECTOR SUM PPV LEVEL OF FOUR HIGHEST RECORDED NIGHT-TIME EVENTS*

It can be seen from the above that LOAEL events (measured externally) were leading to SOAEL events within the master bedroom and, presumably, in other areas of the property as well. There were also 1,187 events within the master bedroom that, if they were caused by construction, would be cause for complaint according to BS 5228-2:2009. It should be noted that people may be more tolerant of vibration events from construction works as there is an understanding that they are temporary and not an ongoing concern, like an operational road.

Importantly for the residents’ immediate concerns for their home, the results of the external monitoring suggested that there were no events likely to cause cosmetic or structural damage to the cottage, as defined in BS 5228-2:2009. The graphs below show our recorded measurement data.

Conclusion

Our survey demonstrated that the improvements to the road had indeed introduced vibration to the property. We established that the new road surface had raised the level of the tarmac enough to create a dip into a rain drainage grid across the road from the cottage that, when hit by a heavy vehicle or one travelling at speed, would induce vibrations across the carriageway and into the nearby home. Whilst these vibrations were unlikely to cause damage to the property, they were nonetheless disturbing for the residents who are now using our data and technical report to seek a resolution with the Local Authority and the Highways Agency. We wish them the best of luck resolving this problem and offer our continued support going forward.

*A RAIN DRAINAGE GRID WAS NOW TOO FAR BELOW THE TARMAC OF THE FINISHED ROAD SURFACE*

Thoughts on Residential Vibration

Obviously, the case study detailed herein is a rare occurrence when a road improvement has made things worse for local residents, but it is far from rare that we are asked to consult on problems of this nature. In the last few months alone, we have been asked to investigate noise and vibration in houses as a result of new speedbumps, a change from tarmac to more attractive brickwork resulting in ‘bumping’ vibrations inside a new estate residence, and even a home plagued by cracking and vibration as a result of improved nearby rail lines.

Vibration in our homes isn’t going to go away without our tackling it head on, but help is at hand in proving the problem in the first place. Whatever your vibration issue may be, the chances are we have seen it before and will be able to help. Give us a call today and take the first step to a smoother future.

Further Reading:

Potholes are drivers' biggest bugbear, RAC finds