Police in Denmark say raising the speed limits on some roads has helped to reduce accident rates.
A two-year trial has seen speed limits on some rural roads increased from 80km/h (50mph) to 90km/h (56mph).
Results showed that some slower drivers raised their speed slightly, while faster drivers slowed down. Although average speeds on the roads remained almost the same, the smaller difference between faster and slower traffic resulted in fewer collisions and fewer deaths, police said.
They said the move had helped reduce frustration among faster drivers, and stopped them from performing dangerous overtaking manoeuvres.
Higher speed limits also helped lower the number of accidents on motorways, according to the study.
RAC spokesman Simon Williams said: "This study has revealed some very interesting, counterintuitive findings which are worthy of further investigation. For obvious reasons, there is a general belief that lower speed limits are needed to save lives, but in discovering that closing the gap between the fastest and slowest vehicles can help to reduce the number of road casualties, the Danish study may well prove to be ground-breaking in years to come. What's needed now are more studies to establish whether this reduction occurs in all instances.
"It is also interesting to know that a similar trend in accident reduction was found on motorways where the speed limit had been raised. The RAC has been supportive of trialling an 80mph speed limit on some sections of our motorways where construction and usage patterns are such that the benefits to users would offset any detrimental safety or environmental impact. Unfortunately, the Government has stated there are now no plans to do such a trial which is disappointing."
The Danish Traffic Police admitted they were initially unsure of the trial.
Spokesman Erik Mather said: "The police are perhaps a little biased on this issue, but we've had to completely change our view now that the experiment has gone on for two years."
Commenting on the findings, Brian Gregory from the Alliance of British Drivers said the trial "vindicated" the view that raising speed limits would improve road safety by reducing speed differentials and driver frustration.
Copyright Press Association 2014