Improving the Sustainability of Transportation: Environmental and Functional Benefits of Right Turn By-Pass Lanes at Roundabouts

Abstract

Abstract:The functional performances of conventional roundabouts (single-lane and multi-lane) and innovative roundabouts (spiral, flower, C and turbo) can be improved through right-turn bypass lanes controlled by stop, yield or free-flow signs. The article presents evaluations of the emissions of air pollutants (carbon dioxide, nitrogen oxides, particle pollution (PM10 and PM2.5)), fuel consumption and construction, management, energetic and environmental costs in roundabouts without or with bypass lanes (controlled by stop, yield or free-flow). The suggested methodology has a general character and can be applied as a multi-parametric criterion for choosing road intersections, although, in the present paper, it has been employed only for a case study. For the aims of this research, we employed recent closed-form formulations to determine roundabout performances; moreover, we used the COPERT IV ® software to estimate air emissions in nine different types of vehicles. Numerous traffic simulations were carried out. The variation in the maximum hourly traffic Qmax and annual traffic QTOT provided the appropriate domains of the examined geometric layouts, both in functional and environmental terms and with regard to generalized costs, estimated for a 10-year period. It resulted that the introduction of right-turn bypasses in all arms of conventional roundabouts with a one ring lane and one lane at the entries (single-lane roundabouts) is the most cost-effective when the flows entering the roundabout are higher than Qmax = 2000 veh/h. Moreover, free-flow bypass lanes always OPEN ACCESSSustainability 2015, 7 5839 provide greater capacity and lower delays than stop-or yield-signaled bypasses. However, with extremely high Qmax values, stop-controlled bypasses guarantee lower fuel consumption, while those with a yield sign lower total costs.

Roundabout Entry Capacity Calculation—A Case Study Based on Roundabouts in Tokyo, Japan, and Tokyo Surroundings

“…The issue of traffic flow behavior in the roundabout area has repeatedly been the subject of scientific research (e.g., [1][2][3][4][5][6]). There are various types of models and the resulting methods in the literature used to calculate the capacity of roundabouts and their individual entries.…”

Analisa Perlambatan Kecepatan Kendaraan Di Penghujung Traffic Light Perempatan Jalan Dengan Menggunakan Persamaan Differensial Derajad Satu. (Studi Kasus Ruas Jalan Ir. H. Soekarno–Kertajaya Indah Surabaya)

“…Sebagai sebuah jalan yang memiliki volume kendaraan yang tinggi dengan luas penampang lintang jalan yang besar akan memungkinkan pergerakan kendaraan yang bersifat dinamis. Dalam usaha untuk menyajikan ruas jalan yang dapat dipergunakan dengan baik dan tepat guna oleh masyarakat transportasi harus ditunjang dengan management transportasi jalan yang baik dan benar [5], [6].…”

Analyzing Risk Factors for Fatality in Urban Traffic Crashes: A Case Study of Wuhan, China

“…With a population of over six million on 890 km 2 in central districts, the number of licensed vehicles was over 1.3 million in 2012 and the number of motor vehicle crashes was likely to continue rising, which could be attributed to the ubiquitous traffic activities in the emerging urbanized area. Therefore, how to maintain public transit safety and sustainability has become a major concern for the department of Road Traffic Administration [4][5][6][7]. Deaths, injuries, property loss resulting from crashes can cause not only personal suffering, but also heavy burdens to society.…”