If you are a cyclist accustomed to riding in traffic, you have probably seen your share of potential car-bike accidents—and perhaps you have even been involved in one or two. If you are a novice, you may not yet be aware of the most common causes of such crashes.

No matter how experienced you are as a cyclist, here are four accident scenarios you will want to be prepared for and do your best to avoid:

1. Someone turning right in front of you

In this situation, a driver passes you on the left, then just up ahead, makes a right-hand turn across your direction of travel. The driver thinks that because you are on a bicycle, you are moving slowly when, in fact, you may be riding nearly as fast as the flow of traffic. To avoid this, ride in the traffic lane. This will force the driver to stay behind you and wait to make the turn.

2. Someone turning left in front of you

An oncoming car may turn left in front of you. You will have no choice but to hit the car if you do not take evasive action. Always be alert to this possibility and if you cannot stop in time, make a right-hand turn. Now you are going in the same direction as the car. When the coast is clear, you can turn around and head back to your chosen route.

3. The opening door

You are riding along parallel to a line of parked cars. Suddenly, a car door flies open. To avoid this potentially devastating crash, you must watch well ahead. Safety experts recommend that you ride in the traffic lane to avoid being “doored.”

4. Exiting a driveway

If you must ride through an area where there are numerous driveways or parking lots, be especially alert to the possibility of cars that might back out into traffic. Again, ride in the traffic lane: It is your right.

One further caution

A personal injury attorney will tell you that every year, thousands of cyclists receive treatment in emergency rooms throughout the Bay Area–many for serious head injuries. You do not want to be a member of this group, so while you are cycling around town, always wear your helmet.