More people were killed or seriously injured (KSI) on Mid Sussex roads than in any other district within the county last year.
The number of collisions with KSI casualties has increased by more than 50 per cent in the past five years in Mid Sussex.
Overall there were 92 collisions which involved KSI casualties - and 109 casualties - between April 2013 and March 2014.
This has increased from just 60 KSI collisions - and 74 casualties - between April 2009 and March 2010.
A spokesman for West Sussex County Council, which provided the stats, said the figures have be collected to compare years, as opposed to districts, because districts vary in size, population, geography, road type and traffic volume.
He added that the rise in the number of crashes in this district is being monitored but added that it may be random because small statistics are subject to fluctuation.
He said: “The rise in the number of KSIs in Mid Sussex is being monitored and once we understand whether this is or not a statistical fluctuation, appropriate action will be taken.”
Horsham ranked second highest for the number of KSI collisions, with 82 collisions and 92 casualties in the last year.
This number has only risen by around 10 per cent since 2009/10.
In West Sussex there were 480 KSI casualties in the past year, compared to 436 five years ago.