Here is some advice, culled from the pages of the Colorado Driver Handbook, on sharing the road with bicycles and motorcycles. You may want to pass this along to your fleet drivers as a friendly reminder. 

The most common motorist-caused car-bicycle or car-motorcycle collision is a motorist turning left in front of an oncoming bicycle or motorcycle. Drivers may fail to see cyclists or may fail to judge the speed of oncoming cyclists. 

As a driver, remember to look for cyclists at the right side of the lane or on the shoulder and then look again. Make sure you see any cyclists and know their speed before you make your left turn.