Motorists who try and beat the Sat Nav journey time are being warned they are putting other drivers at risk.
Road safety chiefs in the west say drivers are increasingly trying to "beat the clock" in a new game which is becoming increasingly common.
The practise is said to be most prevalent among young drivers, but middle-aged drivers and some pensioners are also engaging in it.
Last week, gardaí expressed serious concerns about the rise in road deaths in the west over the past two years, when the national trend has seen a reduction in the number of deaths.
"Unfortunately we are hearing that young drivers are risking their lives and the lives of others by engaging in a 'beat the clock' challenge where they look at trimming off minutes off a sat nav estimated arrival time," said Noel Gibbons, road safety officer with Mayo Co Council.