Until relatively recently, no real data existed on the number of doorings occurring in the city of Chicago or state of Illinois. As a result, we could only make a guess about the seriousness of the problem.

Then progress occurred in 2008 when the city of Chicago passed an ordinance that addressed dooring a cyclist. This meant officers would begin generating better statistics.

And in 2011 Active Trans won a legislative victory by convincing the Illinois Department of Transportation to begin counting doorings as crashes and begin tracking them.

And last summer, Chicago City Council increased the fine for someone who causes a dooring crash to $1,000.

Another victory occurred when the city of Chicago started requiring all taxis to install stickers on their passenger windowsasking their fares to look for cyclists and pedestrians when exiting (see sticker graphic right).

Now we know that 1 out of 5 of Chicago's bicycle crashes occur when someone opens a car doors in the path of a person biking.

There are a number of precautions people biking can take to avoid getting doored. The most important strategy is to avoid the “door zone” as much as possible.

Avoiding the door zone — the area within 4 feet of a car — means riding on the far left side of the bike lane, closer to moving traffic than you may initially be comfortable with.

But as long as the roadway is wide enough and you are riding visibly and predictably in a straight line, the dangers associated with drivers passing too closely are manageable and far less than those of being doored.

If there isn’t enough room to ride four feet from parked cars and still provide passing motorists with the minimum 3 feet of required safe passing distance, it may be safer to move to the center of the lane (“take the lane”) for a brief period to prevent unsafe passing.

If this is only necessary for short distances, and doesn’t create undue delays for motorists, or if you’re travelling at the same speed as traffic, riding in the travel lane is often safer than riding in the “no man’s land” between the travel lane and the door zone.

If you do find it necessary to take the lane for long stretches in order to avoid the door zone and prevent unsafe passing, holding up faster moving traffic in the process, consider an alternate route with calmer traffic.

Also, be on the lookout for doors opening to your left. Whenever passing a line of cars stopped in traffic to your left, keep in mind that passengers may exit midblock, creating another door zone to your left.

If you find yourself trapped between door zones with stopped traffic on the left, parked autos on the right, slow down and proceed with caution while covering your brake. The few extra seconds it may cost you will be worth it in the end.