Rainer Lehmann, Federal Highway Research Institute · Rainer Lehmann Bundesanstalt für Strassenwesen BruederStrasse53 D 51427 Bergisch Gladbach +49(0)2204 43 4500 Thankyou! [email protected]

20-11-18 1

Ramp metering, 20 years of European harmonizationRainer Lehmann, Federal Highway Research Institute

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Utrecht, 14 and 15 November

What is Ramp Metering?Regulation of the inflow to the motorway, depending on the current traffic situation using traffic lights which are installed on both sides of the access ramp.

usually: one vehicle controlin some cases: several vehicle control

Where is an installation useful?• Highly frequented motorways with many incidents and accidents due to the

entering of platoon shaped vehicle inflow• junctions with frequent traffic violations by entering the motorway

(i.e. blocking the acceleration lane)

RAMP METERING - Basics

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RAMP METERING - Algorithm

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Ramp Metering

congestion detection

Detection for GREENDetection for RED

early detection

Traffic Data Detection

Sign 131 StVO (with Flashlight)

Traffic Lights

)(3600

bbKqt

optrZufluss -×+=

• qZufluss: traffic quantity downstream• Kr: correction factor• bopt: optimized occupancy on the right lane

Steering algorithm (ALINEA)



RAMP METERING - Evaluation

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Beforeinstallation

of a

rampmeteringsystem




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Afterinstallation

of a

rampmeteringsystem




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Resultsfor continuous lanes on motorways• an increase of the speed levels at peak times• a better utilization of the available capacity (~ 5%)• a significant reduction in congestion (up to 50%)• a significant reduction of accidents (up to 40%)• a reduction of travel times for the long-distance traffic

for the controlled ramp of the junction• an easier merging in the (still) flowing traffic• an increase of travel times for the urban traffic

(which uses the motorway from junction to junction)• a lower inflow may cause a tailback, that could have consequences

for the urban traffic network.



Centrico – Ramp metering synthesis (2000 - 2001)

Partners involved: Belgium, France, Germany, Luxembourg, The Netherlands, United Kingdom

• Pre-signing on the slip–roadA ramp metering traffic light on a slip–road might is not usual, therefore it is advised to pre-sign the ramp metering signal. It is also advised to use the normal warning sign (red triangle) with traffic lights within the triangle and an additional sign mentioning “ramp metering (in the official language)”.

• The ramp metering traffic lightIt is advised that the outlook of the ramp metering traffic light differs from urban traffic lights. There is common sense to use a yellow contrast shield. This shield has the normal shape (so no rectangular shield).

• The control strategyIt is advised that a ramp metering sign uses a 3 aspect light with green, amber and red. This sign is combined with a one vehicle per green strategy. The one vehicle per green strategy offers a maximum capacity of 800 vehicles / hour per lane.

• Lay-out of the ramp metering systemThere is no advice on detection neither on positioning of the traffic lights except that it is advised to put a low level (left or right) and a high level sign.

RAMP METERING - Harmonisation

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Easyway – Ramp Metering Deployment Guideline (2007 – 2015)

• Pre-signing on the slip–road … CL&FR5, FR6 (should)

Fixed or variable warning pre-signs should be installed on the on-ramp sufficiently upstream of the traffic lights or on the on-ramp entrance (FR5). Additionally, the words “Ramp Metering” or equivalent in native language are added beneath the warning sign (FR6).

• The ramp metering traffic light ... CL&FR7 (should ...???)

Ramp Metering signals should be distinguishable from regular junction signals. It is advised (???) to install a contrasting yellow shield behind the traffic signals, as used in many European countries.

• The control strategy ... CL&FR8, FR9 (should)

• The traffic signals should operate a “Green – Amber - Red” cycle (FR8).

• At locations where ramp metering has a fixed release time to allow a fixed number of vehicles to pass duringeach release phase, the number of vehicles released should be communicated to the driver using a sign (FR9).

• Lay-out of the ramp metering system ... CL&FR1, FR2, FR4 (should), FR3 (may)

• traffic signals should be positioned far from the merging point (FR1) and should be installed per lane (FR4)

• traffic signals should be installed at a low level to face drivers at the beginning of the queue (FR2)

• traffic signals may additionally be installed at a high level (FR3).


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Easyway – Ramp Metering Deployment Guideline (2007 – 2015)

• Pre-signing on the slip–road … CL&FR5, FR6 (should)

Fixed or variable warning pre-signs should be installed on the on-ramp sufficiently upstream of the traffic lights or on the on-ramp entrance (FR5). Additionally, the words “Ramp Metering” or equivalent in native language are added beneath the warning sign (FR6).

• The ramp metering traffic light ... CL&FR7 (should ...???)

Ramp Metering signals should be distinguishable from regular junction signals. It is advised (???) to install a contrasting yellow shield behind the traffic signals, as used in many European countries.

• The control strategy ... CL&FR8, FR9 (should)

• The traffic signals should operate a “Green – Amber - Red” cycle (FR8).

• At locations where ramp metering has a fixed release time to allow a fixed number of vehicles to pass duringeach release phase, the number of vehicles released should be communicated to the driver using a sign (FR9).

• Lay-out of the ramp metering system ... CL&FR1, FR2, FR4 (should), FR3 (may)

• traffic signals should be positioned far from the merging point (FR1) and should be installed per lane (FR4)

• traffic signals should be installed at a low level to face drivers at the beginning of the queue (FR2)

• traffic signals may additionally be installed at a high level (FR3).


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RAMP METERING

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Rainer LehmannBundesanstalt für Strassenwesen

Brueder Strasse 53D 51427 Bergisch Gladbach

+49(0)2204 43 [email protected] Thank you!

Documents

Rainer Lehmann, Federal Highway Research Institute · Rainer Lehmann Bundesanstalt für Strassenwesen BruederStrasse53 D 51427 Bergisch Gladbach +49(0)2204 43 4500 Thankyou! [email protected]