A traffic break is a separation in the flow of traffic along a road or highway. In heavily congested traffic, natural breaks occur rarely. Thus the term traffic break generally refers to the manual separation of traffic, normally conducted by highway patrol officers.

Most such traffic breaks are used to clear a hazardous obstruction from the road ahead or allow a stalled vehicle to safely make its way off the road and onto the shoulder. For example, a highway patrol officer may arrive at the site of the accident and then radio to another officer to initiate a traffic break. The second officer enters traffic before the site of the accident, turns on his/her emergency lights, and begins weaving across multiple lanes to signal that other drivers are to slow down and remain behind the officer. The speed to which the officer slows is based on the amount of time needed to clear the accident ahead. It is not uncommon for an officer to completely stop traffic to yield larger separation. The second officer then radios ahead to the first officer, who is still at the site of the accident, and gives him/her a description of the last vehicle traveling ahead at regular speeds. The first officer will use this information to determine when it is safe to move the accident off the road and onto the shoulder.

Traffic breaks may also be conducted to gradually slow traffic in preparation for a large accident ahead that has caused traffic to stop abruptly. This greatly reduces the chance of subsequent crashes due to motorists not braking in time. Other traffic breaks may give time for minor repairs such as adjusting the placement of a traffic sign. In very rare circumstances, civilian motorists have initiated traffic breaks. For example, in 2004 one Alameda County man ran a traffic break to aid in the emergency landing of a small Cessna 172 on Interstate 680 [1] (free registration required).

When a single traffic break does not allow sufficient time to complete a task, multiple breaks may be conducted in series. This practice is commonly called "running a round robin".