Collisions with cars and other bicycles account for only about one-third of all bike accidents. That means there are plenty of other things to look out for when riding. While many road hazards won't cause more damage than a flat tire or a skid, some can cause more serious harm. The worst hazards knock riders off their bike or cause serious injury, even death. Be ready for anything: keep your head up, your eyes on the road, and stay alert at all times. Slow down whenever hazards are around.
A bicycle should be in excellent shape to safely and quickly react to unexpected occurrences. Brakes should be tight and tires cleaned frequently of the debris that accumulates on them. Carry a spare tire tube or patch kit as well in case sharp objects prove unavoidable.
Getting away from a road hazard is often simply a matter of swerving to the side or braking. Always keep in mind the traffic around you, though. It defeats the purpose to avoid broken glass if you end up colliding with a passing car. Look before you deviate from your path, then swerve right to avoid hazards. Move just enough to avoid danger.
Be especially wary at night or when the sun is blinding, times at which you (and others) are least likely to see danger approaching. Be careful, as well, of dangers at intersections and around corners, and keep an eye out for the road hazards described in the following lists.
Damaged and Unsafe Roads
Potholes, particularly in winter and spring when they're most likely to form.
Loose debris from potholes, often lying near the pothole.
Metal sewer gratings, which can catch bike tires if they are wide enough.
Avoidance techniques. Slow down, check approaching traffic, and safely swerve out of the way.
Glass, which often accumulates at the corners of intersections.
Gravel, particularly sticky bits from newly paved roads.
Twigs, thorns, pine cones, cactus spines, or other debris that has fallen from plants and trees.
Avoidance techniques. Slow down, check approaching traffic, and safely swerve out of the way. In addition, brush off tires frequently to keep sharp pieces from digging into them. You may also want to install a tire-saver device above your wheels that will clear away sharp materials before they cause flats.
Ice, water, and mud, which make brakes less effective.
Oil slicks, which can be difficult to see and may stick to bike tires, making riding treacherous.
Leaves, especially when wet and newly fallen.
Painted streets and pavement, especially when wet and new.
All metal surfaces, including manhole covers, railroad crossings, and bridge expansion joints.
Avoidance techniques. If it is impossible to safely avoid slippery areas, drift through them slowly and smoothly. Ride straight; do not swerve, brake, jerk, or pedal until you are out of the area. Ride over metal tracks perpendicularly or, if you can do it safely, jump them.
Pedestrians, who are not bound by traffic laws and can be unpredictable (watch especially for children).
Parked cars, particularly doors that swing open in front of you.
Wind created by fast moving vehicles as they pass, which can throw you and your bicycle off balance.
Avoidance techniques. Notify pedestrians of your approach with a horn, a bell, or a vocal warning, and give them time to get out of the way. Stay a few feet to the left of parked cars and as far from high-speed vehicles as possible.
Beware of Dog
When you come upon an unleashed and barking dog, don't overreact. Usually the dog means no harm and will lose interest as you pass. But, if a dog is aggressive and begins to chase, you will need to take action. Try to either turn around or speed up to outrun it. While taking care to avoid a collision with the dog, don't let the animal distract you from the road. Firmly and loudly yell “Stay!” or “No!” at the dog. If that doesn't work, raise your hand as if to throw something at it (but don't actually throw anything). As a last resort, spray some water from your water bottle into the dog's face (some cyclists use a temporarily blinding ammonia solution, though that's usually not necessary). If you must get off your bike, use the bike as a barrier between you and the dog. If the dog's harassment becomes a regular occurrence, speak to the dog's owner or report the dog to the police.