From the missionary handbook

If you ride a bicycle, learn bicycle safety rules, use caution, obey all traffic rules, and use proper hand signals. Avoid riding after dark, in heavy traffic, or in bad weather. You may need to adapt travel to weather conditions or even cancel some activities in severe weather. In many situations, you and your companion should not ride bicycles side-by-side or follow too closely, but you should always stay within sight of each other.
Always wear a helmet that is safety certified by a recognized industry group. Keep your bicycle in good working order. Make sure it has a working headlight and taillight, a clearly visible rear reflector, and reflectors on both sides. As appropriate, wear reflective gear on your clothing.
Lock and secure your bicycle when you are not riding it. If it is lost, stolen, or damaged, you will need to replace or repair it from your personal funds.