The number of casualties from crashes caused by slow drivers increased by almost a third last year, figures show.
Press Association analysis of Department for Transport data shows 175 people were injured and two were killed in such accidents on Britain’s roads in 2017.
This represents a 31% increase in total casualties from the previous 12 months.
The figures take into account crashes when someone is driving too slow for the conditions or a slow moving vehicle was a contributory factor.
AA president Edmund King warned that “driving like a snail can be as dangerous as driving like a cheetah”.
Too many motorway users hog the middle lane and drive “far below the speed limit” which can lead to undertaking, tailgating, congestion and road rage, he said.
Mr King revealed he often sees motorists slow down and hesitate when joining a motorway rather than matching their speed to fit into the traffic flow.
“I was in a queue of five cars joining the M3 recently when the lead driver was driving at approximately 25 mph,” he added. “It was incredibly dangerous.”
A poll of 2,000 UK drivers commissioned by carmaker Hyundai earlier this year found “someone driving too slowly in front of you” is the seventh most common reason motorists swear when they are behind the wheel.
Minimum speeds are rare on UK roads, but do exist in some high-risk locations such as tunnels. These are displayed by a round blue sign with a white number.
Driving too slowly on any road can result in the motorist being penalised for careless driving, which normally carries a £100 fine and three points on a licence.
If a case goes to court the maximum penalty is £5,000, up to nine points on a licence and disqualification from driving.
Research by Australia’s Queensland University of Technology published last year which found that the risk of an accident can be increased by motorists who slow down when they use their mobile phone.
The study indicated that this is due to nose-to-tail crashes, congestion and frustrated drivers performing aggressive overtaking manoeuvres.
A DfT spokesman said: “Careless driving including driving too slowly is an offence and anyone caught faces prosecution.”
Neil Greig, director of policy and research at motoring campaign organisation IAM Roadsmart, said: “Slow drivers are just one extra hazard that any good driver must be able to deal with.
“By using the key advanced driving skills of observation, anticipation and patience, anyone should be able to cope with a hesitant or tardy person on the road.
“If you run into the rear of someone then it’s most likely insurers will see it as your fault.”