Release time

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Traffic lights green.svg

In road traffic engineering, the release time is the time within which a traffic flow is allowed to pass a signal-controlled intersection .

For the sake of simplicity, the release time is also referred to as the green time , because the release signal for the traffic flow usually shows green. The term green time is often found in cases in which the green color is not used at all, for example with the bar signals for public transport.

The temporal beginning of the release time is often referred to as green beginning , the end of the Greening called. Any transitional terms used (e.g. red / yellow , yellow , point on public transport) do not count as part of the clearance time.

The " Guidelines for traffic light systems " (RiLSA) prescribe a minimum release time of 5 seconds. In addition, it must be guaranteed for pedestrians that they have covered half the pedestrian ford (at a standard speed of 1.2 m / s) or the entire pedestrian ford if it is equipped for the blind and visually impaired .

Percentage of green time

The number of conflicting directions must divide the cycle time by the signal time plan of the traffic light system. These can be pre-programmed according to the program or with a time switch according to expected requirements, or they can be influenced by equipping them with sensors such as PIR sensors , induction loops or image recognition from cameras to measure needs by means of image comparison. In the case of a Seagull Intersection , the green time can be 100% for a driving relation.

Green time tour

In the case of traffic light control , a distinction must be made between continuous and non-continuous green time management. With continuous green time management , the release time is allocated within a green wave according to the continuous green belt. In the case of discontinuous green time management , additional release time is introduced in the form of lead or lag times.

Definitions

The release time is used in various modifications within the signal program .

  • The release expiry time refers to the time between the first request for the blocked traffic direction and the end of the release time of the current phase.
  • The release sequence describes the time by which a current phase in a signal program influenced by the road user can be extended.
  • The release extension time is the length of time by which a release time is extended in a signal program (release time extension).
  • With the release time adjustment , the release time is temporarily shortened or extended within a fixed-time signal program.
  • The clearance time requirement is a time value that a certain number of vehicles or pedestrians need in order to drive over the stop line or to enter the pedestrian ford.
  • The release time offset is the time difference between the start of the release times at two light signal generators, past which a certain traffic flow flows past one after the other.