See Road Hazards and Alerts for specific issues in Boulder County.

Always be on the lookout for potholes, dips, and parallel cracks.  Parallel cracks (those extending in the same direction as you are riding) are especially dangerous because they may appear to be repaired from previous attempts to seal them, but have re-opened over the winter.  Also, beware of hard-to-see sheets of ice from melting snow in bike path underpasses and other places shielded from direct sun.

—Seams and cracks.  When these run parallel to your direction of travel they can trap your front wheel and take you down. Concrete roads are notorious for wheel-eating ruts, but they can occur on blacktop, too, due to poor road construction or settling. Sometimes deep grooves carved by farm machinery or other heavy equipment appear when you least expect them.

Be vigilant, particularly when entering a shaded section that makes fissures hard to see. Your objective, of course, is to keep your wheels out of them.   If you’re trapped, don’t try to turn out. That’s likely to make you crash. Stop pedaling and either continue in the rut until it ends, or jump the bike up and to the side to untrap the wheels. This should only be tried by advanced riders who have practiced it under good conditions.

—Rough or broken pavement.  When approaching long sections with a gnarly surface, slide to the rear of the saddle, shift to the next higher gear, grip the bar top or brake lever hoods, and steadily pedal through. The slightly bigger gear adds resistance and slows your cadence so you can pedal smoother with less bike chatter.

—Painted lines.  Be wary entering any corner in urban areas where there may be painted crosswalks or other road markings, especially if they’re wet. Slow down and do your best to cross them with your bike perpendicular.

—Wet metal.  Anything metal and wet is ultra slippery. This includes manhole covers, plates, grates, metal bridge surfaces, railroad tracks, and so on. Again, reduce speed for safety but not so much that you can’t ride across the danger without pedaling. Coast in at a right angle with your bike perpendicular.

—Fallen leaves.  Leaves usually aren’t a problem when you’re riding straight through them (although they may cover potholes, seams or other dangers). But in a corner, watch out. If there is wetness between or under the leaves, they can be slippery and cause you to slide down. In the off season when there are freezing temperatures overnight, what appear to be dry leaves can actually have frost between or ice underneath.

—Gravel and sand.  When the loose stuff is on a flat stretch, use the same technique described for rough or broken pavement. When sand or gravel is in a turn, initiate your turn before reaching it. Then straighten the bike just before you cross. If your bike is upright on a slippery patch, it’s much less likely to slide out from under you. Once safely across, lean the bike again to complete the turn.

Never grab the brakes while the bike is angled over on any slippery surface. A braked wheel tends to go straight, so if you clamp on the stoppers while you’re leaning, you’ll almost certainly go down.