You hear a lot about the risks involved with cycling and the odds of an accident. You hear how getting hit on your bike is far more dangerous than getting hit in your car. It makes it seem like, when considering the overall impact on your health, you would be far better off to drive your car to work, rather than riding your bike.
You're riding down the bike lane when an SUV goes by. There's plenty of space to move over, but the driver neglects to do so, coming within a foot or so of your bike. It's way too close. On top of that, the SUV is going about 60 miles per hour, even though you are clearly in a 45 MPH zone. As the vehicle goes by, you look up and see that the driver is texting and looking down as they pass you. While you watch, the SUV actually drifts into the bike lane about 20 feet ahead of you.
The danger of riding a bike in the city stems, to a large degree, from the sheer ignorance that many drivers have regarding how to drive around bikes. They simply do not understand how to do it properly. They're not trying to put you in danger when you're out for a ride, but their lack of knowledge leads to critical mistakes -- and you're the one who pays the price.