Accident migration refers to a situation where action to reduce road traffic accidents in one place may result in those accidents resurfacing elsewhere.

For example, an accident blackspot

Accident blackspot

An accident blackspot is a term used in road safety management to denote a place where road traffic accidents have historically been concentrated...

 may occur at a dangerous bend. The treatment for this may be to increase signage, post an advisory speed limit, apply a high-friction road surface, add crash barriers or any one of a number of other visible interventions.

The immediate result may be to reduce collisions at the bend, but the subconscious relaxation on leaving the "dangerous" bend may cause drivers to act with fractionally less care on the rest of the road, resulting in an increase in collisions elsewhere on the road, and no overall improvement over the area.

In the same way, increasing familiarity with the treated area will often result in a reduction over time to the previous level of care (regression to the mean) and may result in faster speeds around the bend due to perceived increased safety (risk compensation

Risk compensation

In ethology, risk compensation is an effect whereby individual people may tend to adjust their behavior in response to perceived changes in risk. It is seen as self-evident that individuals will tend to behave in a more cautious manner if their perception of risk or danger increases...

).