Lincolnshire Police say they are doing all they can to cut the number of deaths on the county's roads.
Road deaths continue to rise in the county.
They admit the last week has been one of the worst in recent years for deaths and serious injuries.
Six people have been killed over the last seven days, bringing this year's total so far to 50.
But a senior officer has warned drivers themselves carry a burden of responsibility when it come to safer motoring.
Four people were killed over the weekend, including two Lincolnshire schoolgirls aged 11 and 12, in a crash on the B1191 at Martin Fen near Woodhall Spa.
Nearby residents felt the uneven condition of the road and its deceptive speed had contributed to the accident.
But the police said that while they took the issue extremely seriously, there was only so much enforcement could achieve and there were other important factors.
Lincolnshire's Assistant Chief Constable, Peter Davies, said: "Although I cannot comment on this most recent incident, the pattern clearly is people not driving to the road conditions.
"In this weekend just gone we had an additional 13 cars go off the road, no collisions with other cars, 13 cars go off the roads and there, thanks to the grace of God, go 13 drivers and who knows how many passengers?"
Mr Davies also pointed out the three most consistent factors in road fatalities in the county remained the same.
These are excessive speed, all the people in the car not wearing seat belts and cars not being in a fit mechanical condition for the roads.
He also rejected the idea that most accidents were caused by drivers unfamiliar with the county's roads.
Mr Davies said: "The sad and tragic truth of it are that most of the fatalities are local people.
"All four fatalities this weekend were Lincolnshire people on Lincolnshire's roads.
"Most of the people we are tragically losing at the moment know the roads."
He also praised the work of the Lincolnshire Road Safety Partnership and county council and said there was a major meeting concerning the issue at the county offices on Thursday.