Performance Study of a Rotary Under Heterogenous Traffic Flow Conditions (A Case Study Of Falomo - Awolowo Intersection, Eti-Osa Local Government, Lagos, Nigeria)
May 2017
Adewale Olutaiwo, Elewuro Hairu O.

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Abstract

The Falomo-Awolowo roundabout intersection (a 4-leg approach) was taken as a typical case study for performance analysis. The traffic conditions at the roundabout are heterogeneous. Entry capacity versus circulating flow relationship was determined, evaluated and compared using the TransModeler software, HCM Capacity Model (2000 and 2010), N.C.H.R.P Report 572 Capacity Model and the Modified Tanner's Capacity model. The results indicated that the circulating –flow capacity does not exceed the 1800 veh/h (2-Lane roundabout circulating-flow capacity limit). The entry capacity of HCM 2000 Capacity Model and N.C.H.R.P Report 572 Capacity Model are similar while there is an increase of entry capacity from the Modified Tanner's Capacity model. The degree of saturation (v/c ratio) on all the approaches is greater than 0.85, their LOS (F - Forced flow) because their average delay is greater than 50seconds (HCM Capacity Model (2000 and 2010) and N.C.H.R.P Report 572 Capacity Model). The average delay (Modified Tanner's Capacity model) is 19 seconds (LOS C–stable flow), 30seconds (LOS D–approaching unstable flow) and 76 seconds (LOS F – Forced flow). The TransModeler software result shows a higher entry capacity, higher average delays and poor LOS (LOS F – Forced flow).Keywords: Rotary Intersections; Heterogeneous Traffic Flow; Capacity; Conflicting –Movements; Level of Service.

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Metrics Icon 47 views  //  14 downloads