One debate that goes on is about bike lanes. There are many good reasons for having them and strong ones against it. The goal is shared. Many cyclists would like to be safer on the roads that they pay for using their preferred method of transportation.
One argument is that bike lanes reinforces the minds of drivers that bikes belong on the road. They see the lanes and will understand that part of that road is for the bikes and to be aware. Those who disagree with bike lanes say that this only reinforces the drive that bikes should only be on specially marked roads. If a road is not marked the driver will assume that this road is not for bikes and will not watch for them on roads that are not marked.
Those in favor of bike lanes make the argument that having these lanes will at least assure that part of the road will be nice and smooth. The city could work on making sure that this part of the road is free from potholes and other hazards. Those against the lanes say that this is not attainable and bikers will still have to swerve and dodge these problem areas in the road and it might be easier to do on a larger road.
One thing both sides are in favor of is keeping bike lanes off the left side of the street. Some cities for one reason or another have added bike lanes that go towards oncoming traffic. This puts the cyclists in even more danger which is not a positive solution.
Biking is a pretty important. If more biked, there would be some health benefits and much less money needed to repair the roads. How to go about it safely with distracted drivers is always going to be a difficult issue to actually resolve.