Kajian Ulang Perencanaan Geometrik Simpang Simpang Tak Bersinyal Berdasarkan Highway Capacity Manual

Simpang Empat Jeuram Nagan Raya sering disebutkan oleh masyarakat setempat ”Simpang Peut” merupakan jalur utama jalan arteri kota melayani pergerakan lalu lintas antar kabupaten atau antar provinsi, yang berada di Kecamatan Kuala Kabupaten Nagan Raya. Simpang tersebut memiliki empat lengan, melayani arus 4 lajur jalan utama bermedian dan 2 lajur jalan minor menghubungkan jalur arah perkantoran, perumahan penduduk, perdagangan dan sebagai jalur menuju ke pusat kota. Permasalahan diangkat dan juga menjadi tujuan penelitian bagaimana kinerja persimpangan terhadap volume lalu lintas terjadi di empat lengan dan membedakan selisih perhitungan sekarang terhadap penelitian terdahulu. Batasan pembahasan yakni lokasi penelitian di Simpang Empat Jeuram, kinerja simpang berdasarkan metode HCM 1993, hambatan samping dan tidak memperkirakan penelitian terdahulu. Berdasarkan hasil, volume arus yang terjadi 3.310 smp/jam dengan komposisi arus kendaraan 2.789 smp/jam. Kapasitas 4.009 smp/jam berada diatas volume yang ada dikategorikan tidak macet atau tidak jenuh. Hambatan samping 1.328 kejadian dikategorikan daerah niaga dan aktivitas pasar sisi jalan sangat tinggi. Derajat kejenuhan 0.70 < DS (DS < 0.80 - 0.90) dengan rata-rata delay 7.95 detik/smp dan panjang antrian 40% - 20% dengan tingkat pelayanan D dimana arus tidak stabil dan kadang harus memperlambat kecepatan 43 km/jam. Terkait penelitian terdahulu menunjukkan hasil signifikan, karena peningkatan kendaraan terus meningkat 75% dalam kurun waktu 3 tahun terakhir.

Identification of Operational Design Domain for Autonomous Truck Mounted Attenuator System on Multilane Highways

The Autonomous Truck Mounted Attenuator (ATMA) vehicle system is a technology that leverages connected and automated vehicle (CAV) capabilities for maintenance of transportation infrastructure. Promoted by FHWA and state departments of transportation (DOTs), it is a niche CAV application in leader–follower style, intended to remove DOT workers from the following maintenance truck, to reduce fatalities in work zones. Because practicable guidance for deployment of this technology is largely missing in MUTCD, state DOTs have been making their own deployment criteria. In this manuscript, we focus on the operational design domain (ODD) problem—under what traffic conditions should ATMA be deployed. Modeling efforts are first focused on the derivation of an effective discharge rate that can be associated with a moving bottleneck caused by slow-moving ATMA vehicles on a multilane highway. Then, based on the demand input and discharge rates, microscopic traffic flow models calculate vehicle delay and density, which the Highway Capacity Manual (HCM) suggests are key indicators of a multilane highway’s level of service (LOS). In this way, the linkage between AADT and LOS is analytically established. NGSIM data is used for the model validation and shows that the developed model correctly captures the effective discharge rate discount caused by moving bottlenecks. The modeling results demonstrate that roadway performance is sensitive to the K factor and D factor, as well as the operating speed of ATMA and, if LOS = C is a desirable design objective, a good AADT threshold to use would be around 40,000 vehicles per day.

Effect of increasing rate of tricycles on saturation flows at signalized intersections in Uyo, Akwa Ibom State, Nigeria

This study involves understanding the effect of tricycles on saturation flow rate at signalized intersections. The goal is to show that intersection dominated by tricycle experience congestion especially at peak periods (morning and evening). This was done by collecting vehicular traffic data, signal timing and geometric data from five (5) signalized intersections at ten (10) cycles. The period covered October, 2015 to June, 2016 for four working days of the week (Mondays, Tuesdays, Wednesdays, and Fridays), between the hours of 7:30 am–9:30 am and 4:30 pm– 6:30 pm. The duration of data collected covered both rainy and dry seasons. Average vehicular departure time during green time was determined and saturation flow obtained through field measurement by the ratio of average vehicular departure time to green time. Highway Capacity Manual method was also used to obtain saturation flow at each study approach. Saturation flow obtained through field measurement and Highway Capacity Manual were compared using independent t-test having t-value of 4.239 and P-value of 0.000 at 20 degree of freedom were obtained. The analysis indicated that P-value is less than 0.05, hence the mean of Highway Capacity Manual 2000 Model (5918.60) was significantly higher than the field measurement (4687.50). The result indicated that the increasing rate of tricycle with non-lane discipline causes congestion at signalized intersection. The findings suggest that the widely used Highway Capacity Manual is not appropriate for determining saturation flow for a mixed traffic with increasing rate of tricycle coupled with non-lane discipline traffic condition. From the analysis, it is recommended that Government should give priority to use of buses as a means of mass transit system so that it can accommodate more commuters than tricycle.

Measuring Control Delays at Signalized Intersections in Mixed Traffic Conditions

Control delay is the key performance indicator of a signalized intersection that defines the level of service. Several models have been developed in previous research work for estimating control delays, but many of them were based on homogeneous traffic conditions. In the present study, an Open Street Map (OSM) tracker mobile application was used to measure control delays from the field. A non-linear model was developed in the present study for estimating control delays in mixed traffic conditions using a MATLAB fitting tool. The field delay is compared with the developed non-linear model delay along with the Indian Highway Capacity manual (INDO HCM) and Highway Capacity Manual (HCM) models. The control delay estimated using the model developed in the present study shows a close relation with the field delay obtained using an OSM tracker when compared to that obtained using the INDO HCM and HCM models. Therefore, the OSM tracker mobile application can be used as a field control delay measuring technique.

Avaliação do efeito de faixas adicionais de subida em segmentos de rodovias de pista simples

O novo método do Highway Capacity Manual (HCM) para calcular a capacidade e o nível de serviço de rodovias de pista simples deverá ser, provavelmente, baseado na Densidade de Veículos em Pelotões (FD). No Brasil, há poucos estudos que determinam o impacto de faixas adicionais em rodovias de pista simples, sobretudo envolvendo FD, que é o objetivo geral deste trabalho. Para isso, foi obtido um conjunto de dados de tráfego em segmentos de rodovia para calibrar e validar o simulador de tráfego VISSIM. Com uma versão recalibrada do simulador, foram gerados dados de tráfego em segmentos viários hipotéticos com e sem faixas adicionais, com os quais foram ajustados modelos de tráfego fluxo x FD. Os resultados da análise dos modelos indicaram que a proposta deste trabalho produziu valores de nível de serviço e de FD mais aderentes aos valores que foram observados em campo.