Operating Cost, Fuel Consumption and Pollutant Emission Savings at a Roundabout with METERING SIGNALS

Estimation of operating cost, fuel consumption and pollutant emissions for evaluating intersection traffic conditions is useful for design, operations and planning purposes in traffic management. A four-mode elemental (drive cycle) model is used for estimating fuel consumption, emissions and operating cost. The drive cycles vary significantly for different intersection types (roundabout, signalised, sign-controlled), for different signal phasings and timings, and for different congestion levels. A case study is presented comparing a roundabout with and without metering signals in terms of operating cost, fuel consumption and pollutant emissions as well as delay and degree of saturation. When low capacity conditions occur during peak demand flow periods, the use of part-time metering signals is a cost-effective measure to avoid the need for a fully-signalized intersection treatment. The case study shows the effectiveness of this method of traffic control.