Harsh winter weather and bad drivers are being blamed for an increase in local school bus accidents.

New figures presented to the public school board on Monday by Student Transportation Services of Waterloo Region show that accidents involving school buses in the 2013-2014 school year increased to 40, from 37 accidents the year before. Three students were injured last year, while four students were injured the year before.

While the agency that coordinates school buses for local school boards says its safety record is still good, the number of collisions are up from an average of 5.45 per every million kilometres collectively travelled by buses in the 2012-2013 school year to eight in 2013-2014. The agency's goal is to decrease that rate to 4.4 collisions per every million kilometres collectively travelled.

"A lot are non-preventable," Benoit Bourgeault, the general manager of Student Transportation Services, saying the sudden uptick in accidents can be blamed mostly on last year's unusually cold winter.

"What we experienced was a difficult winter after a number of years of very mild winters, with snow banks building up, a fair amount of snow and a few fender benders."

However, Bourgault says the other factor is bad drivers, who don't always drive according to the conditions or, in some cases, fail to notice the hulking yellow school bus that's right in front of them.

"It's a big vehicle in small streets, and it's amazing how many times people do not see the school bus with flashing lights and rear end the school bus," he said.

No data was available for the current school year, which has yet to run its course.