Estimation of turning adjustment factors at signalised intersections according to Malaysian traffic conditions
| dc.contributor.author | Quazi, Sazzad Hossain | |
| dc.date.accessioned | 2014-11-14T07:57:30Z | |
| dc.date.available | 2014-11-14T07:57:30Z | |
| dc.date.issued | 2007 | |
| dc.description | Ph.D | en_US |
| dc.description.abstract | Turning movements at signalised intersections have been a major concern of traffic planners and road authorities for decades. One of the most important factors affecting the saturation flow at signalised intersection is turning (left-turn, right-turn and U-turn) traffic. The presence of turning vehicles tends to lower the saturation flow as well as the capacity and cause excessive delay at an intersection. Because of this the estimation of turning adjustment factor is required to make accurate assessments of the saturation flow as well as capacity of intersections. The United States Highway Capacity Manual 2000 (US HCM 2000) has been extensively used in Malaysia to estimate the turning adjustment factors (left-turn and right-turn) and other related analysis and design at signalised intersections. Recently the Malaysian Highway Capacity Manual 2006 (MHCM 2006) has been introduced used for this purpose. The existing US HCM 2000 and the MHCM 2006 do not take into consideration the turning radius for the estimation of left-turn and right-turn adjustment factors. The effects of U-turns are not separated in both manuals (US HCM 2000 and MHCM 2006) where the U-turning vehicles are considered as right-turning vehicles (left-turn in U.S.A.) The aim of this study is to estimate the left-turn and right-turn adjustment factors from shared and exclusive lanes considering turning radius and proportion of turning vehicles and to estimate the U-turn adjustment factor from share right and U-turn lane for protected phasing at signalised intersection according to Malaysian traffic conditions. To carry out analysis, traffic data were collected at signalised intersections in different cities in Malaysia. In this study, eighteen intersections with shared and excusive left-turn lanes, thirty intersections with shared and exclusive right-turn lanes, and thirteen intersections with shared (exclusive right-turn with U-turn) and exclusive U-turn lanes were selected. Audio cassette recorder was used to collect the traffic data. The advantage of using audio cassette recorder is that the time involved in analysis is fairly short and large number of sites can be studied. Recorded data were transferred from audio cassette to computer using the software BancianVer 2001. The left-turn, right-turn and U-turn adjustment factors are estimated using regression analysis. The results indicate that the left-turn and right-turn adjustment factors decreases as the proportion of turning vehicles increases and the turning radius decreases. The estimated left-turn and right-turn adjustment factors using the proposed method give higher value than that of the MHCM 2006. The results of the U-turn adjustment factor show that the U-turn adjustment factor decreases with an increase of proportion of U-turning vehicles. The study results show that on average the U-turn adjustment factor decreases 2.25% for every 10% increase of U-turn percentage. It is also found that the daily conflict of U-turn with conflicting left-turn from opposite lanes is 1.4 times more than the U-turn same direction conflicts. Finally, the findings of this study indicate that the proposed method for estimating the turning adjustment factors is found more accurate. Moreover, it is simple enough to understand. These adjustment factors are able to forecast the saturation flows precisely which represents the actual traffic and roadway conditions in Malaysia. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/525 | |
| dc.language.iso | en | en_US |
| dc.subject | Civil Engineering | en_US |
| dc.subject | Turning Adjustment | en_US |
| dc.title | Estimation of turning adjustment factors at signalised intersections according to Malaysian traffic conditions | en_US |
| dc.type | Thesis | en_US |
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