Driving the same route is safer.

Not when you die a heart attack. The increase in health from cycling outweighs the risk of death in the region of 50 to 1 ( see meta-study at http://www.ubcmj.com/pdf/ubcmj_3_2_2012_6-11.pdf)

Obviously, if you do plenty of exercise already, this may be more of a moot point, but if you are even slightly overweight or unfit, get on your bike.