(Also known as bulk or platoon metering) permit two or more vehicles to enter the freeway facility per green cycle. Typically two and in some cases three vehicles are permitted to pass the ramp meter per each green signal indication. Although this approach doubles or triples the throughput of vehicles per green indication, similar results cannot be expected for vehicle throughput as longer cycle lengths are required. Compared to the one vehicle per green approach, the multiple vehicle per green approach results, on average, in an increase in throughput of 200-400 veh/h
It describes a strategy to handle a higher demand.
There is also the possibility to let pass more than one car per cycle on the mainline. It is not possible to double the flow rate of the version with one car per green because of longer green and red phases to avoid uncertainty of the drivers. [14]-(p.7) This option is in contrast to the goal of ramp metering to split arriving platoons into single units. It is not recommended to let more than 3 cars pass the ramp at once. [1]-(p.6)
However, field observations have shown that a 4-second cycle is too short to achieve the requirement that each vehicle must stop before proceeding. Also, any indecision on the part of a
passenger-car driver may cause the consumption of two cycles per vehicle. A more reasonable cycle is around 4.5 seconds, obtained by increasing the red time to 2.5 seconds. This increase results in a meter capacity of 800 VPH.
It describes a strategy to handle a higher demand