A person who causes damage to another person’s property is liable to pay compensation even if the damage was caused unintentionally. One example is a person who swings an umbrella while walking in a public domain, and accidentally breaks another person’s eggs. Although one is certainly entitled to walk through the public domain, the other individual – who was carrying the eggs – also has the right to be there. Therefore, the person who broke the eggs is required to compensate for the loss, even though he had no intention to cause damage and did not even see the other pedestrian. A person who walks in a public domain bears the responsibility to exercise caution not to cause damage to other people or their property, and one who does cause damage while walking through a public domain is held liable.

If two pedestrians walking through a public domain collide, causing damage to one of the pedestrians’ property, such as if his eyeglasses break, the other pedestrian is not held liable. Walking is a perfectly acceptable activity in a public domain, and thus since the damage was caused as a result of their both acting normally in a public domain, they are both considered guilty and there is no liability.

This Halacha applies only to walking; it does not apply to running. Running is not an acceptable activity in a public domain, and therefore if a person runs through a public area and collides with a fellow pedestrian, causing damage to his belongings, he is liable for the damages. Since he acted in an abnormal fashion, he bears responsibility for the damages caused by his running. The exception to this rule is Ereb Shabbat, when it is considered normal and acceptable to run through a public area, due to the pressures of preparing for Shabbat. It is expected and accepted that people rush on Ereb Shabbat to make their purchases and run errands in preparation for Shabbat, and therefore if a person causes damage by colliding with somebody while running through a public area on Friday, he is absolved of liability. Thus, if a person takes his fellow to a Bet Din claiming compensation for damages caused when the defendant was running through a public area, the Bet Din’s ruling will depend on when the incident occurred. If this took place on Friday, the defendant will not be held liable for the damages, whereas if the incident occurred during a normal weekday, he would, indeed, bear liability.

Of course, this does not apply if the defendant caused damage on Friday by engaging in an abnormal activity, such as swinging his umbrella. He is exempt if he caused damage by running on Friday, because running is considered acceptable as part of the rush to prepare for Shabbat. Quite obviously, however, if he caused damage through irresponsible behavior in the public domain, he is certainly liable to pay for the damage.

Summary: If two people collide while walking in a public area, causing damage to one pedestrian’s property, the other is not held liable. If, however, a person caused damage through unacceptable conduct in a public area, such as swinging an umbrella or running, he is liable to pay for the damage. The exception to this rule is a person who caused damage by running on Ereb Shabbat, since running on Ereb Shabbat in a public area is considered acceptable in light of the rush to complete Shabbat preparations.