The simplest ideas to save lives are the best
The addition of new designs of rumble strips on the edges of single-carriageway A-roads would help towards Government targets to reduce road deaths and injuries.
Easy to install, cheap to maintain and with a long life, they would reduce the number of people killed and injured, due to vehicles leaving the road.
Although lane departure warning systems are mandatory on new vehicles, they form only a small proportion of the total vehicles on UK roads, and can be switched off.
All UK motorways and dual carriageways have road-side/shoulder rumble strip present along the entire length.
But only 2% of the single carriageway length has shoulder rumble strips, and it is not a design requirement.
The is the verdict of a scientific report by TRL, commissioned by government agency Highways England, which also says that the measure would have a high a Benefit-to-Cost Ratio (BCR) of “at least 12 to 1.”
The report also examines different types of rumble strips and concludes that Sinusoidal rumble strip designs (pictured, below) are a better alternative for reducing the external noise levels while keeping the driver awareness at an acceptable level.
Sinusoidal rumble strips are created by milling a pattern into the tarmac, rather than adding raised ribs (‘lumps of paint') as is the current UK practice. They are also safer for motorcyclists.
The report - Safer Verges Part II - is a second round of more detailed work into the subject after an initial study in 2016 into road safety recommended that more research into the subject should be undertaken to establish if the widespread introduction of rumble strips would be beneficial.
The Road Investment Strategy (RIS) by the Department for Transport (DfT) sets out a target of 40% reduction of deaths and serious injuries on the Strategic Road Network (SRN) by the end of 2020 and a 2040 target for the number of people killed and seriously injured on the SRN to approach zero.
The report says: “One of the most desirable methods for improving roadside safety is to prevent vehicles from leaving the carriageway in the first place.
“Vehicles can leave their intended path for a number of reasons, including:
- Driver impairment
- In-vehicle distraction
- External distraction
“All of these are shown to be a problem within the SRN through various research studies and statistics.
“Drivers who drift off the road due to any of these reasons may fail to realise they have done so, and therefore make little attempt to brake and are more likely to have a serious incident if they hit a roadside object or collide with an oncoming vehicle.”
The report makes four recommendations:
- Carry out a study to see the local effects and the benefits of modern rumble strip types, such as the sinusoidal design
- The use of rumble strip as a centre line treatment on single carriageway roads be permitted
- A trial of centre line and shoulder rumble strips to identify the maximum reductions in incident frequency with the use of milled rumble strips
- Any trial rumble strip installation is accompanied by an Empirical Bayesian research study, so that their effect on the UK road environment can be quantified
Download the report here