Tag:traffic_signals=ramp_meter
 traffic_signals = ramp_meter
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| Description |
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A signal on an onramp to a motorway that limits traffic to promote free-flowing traffic. 
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| Rendering in OSM Carto |
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| Group: highways |
| Used on these elements |
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| Requires |
| Status: in use |
| Tools for this tag |
Ramp meters are signalling devices typically found on motorway on-ramps to control the flow rate of joining traffic to promote free-flowing traffic. May be activated only during rush hours or periods of heavy traffic. They typically limit the number of cars per cycle, typically varying from 1-3 vehicles.
Ramp meter signals are most commonly placed on on-ramps to motorways or similar roads, but they also occur in other contexts, for example on on-ramps to roundabouts. Unlike signalised roundabouts, priority rules are not affected by the signals, and not all entrances to the roundabout need to have signals. These roundabout ramp meters only seek to avoid a too high traffic inflow from the direction where they are installed, similar to ramp meters on motorways.
Tagging
| Key | Value | Element | Comment |
|---|---|---|---|
| highway | traffic_signals | 
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Required. |
| traffic_signals:direction | forward/backward |
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Typically "forward". Indicates the traffic signals signal only the traffic moving in the same direction as the OSM (highway) way upon which the they are placed: forward; or in the reverse direction: backward.
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| ref | * |
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Reference number or code, if present or at least assigned to specific traffic lights. |
| traffic_signals:countdown | yes / no |
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When there is display a countdown of the remaining time to wait or the time remaining where crossing. |
Real World Examples
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Ramp meter in California, USA -
Ramp meter from Miller Park Way to I-94 east in Milwaukee, WI USA -
Completed Ramp Metering site prior to signal activation on entry slip road to the A19 in Middlesbrough, UK -
Ramp Meter in Auckland, NZ
Rendering
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BlindMap. Pedestrian traffic signals with sound
See also
traffic_signals=bus_priorityfor a similar traffic light to give priority to busses.traffic_signals=emergencyfor a similar traffic light to give priority to emergency vehicles.
