microsoft word - easts 2009 c5-kalayaan rev

Proceedings of the Eastern Asia Society for Transportation Studies, Vol.8, 2009

ELEVATED U-TURNS IN METRO MANILA

Reigna Jewel Ritz M. MACABABBAD Graduate Student Institute of Civil Engineering University of the Philippines Diliman, Quezon City Philippines 1101 E-mail: [email protected]

Ricardo G. SIGUA, Dr. Eng. Professor, Institute of Civil Engineering Affiliate Faculty, National Center for Transportation Studies University of the Philippines Diliman, Quezon City Philippines 1101 Fax: +63-2-9288305 E-mail: [email protected]

Eduardo R. PO, Jr. Graduate Student Institute of Civil Engineering University of the Philippines Diliman, Quezon City Philippines 1101 E-mail: [email protected]

Abstract: This paper provides information on the configuration of the Elevated U-turn that is finally constructed along C5 as alternative to the initial C5/Kalayaan underpass and C5/Vargas-Lanuza overpass plans. It further gives an analysis on its expected performance as an infrastructure that will meet the current and future traffic demand. Specifically, the level of service at peak hours are computed and assessed. Further qualitative analysis discussed the advantages and disadvantages of the U-turn flyover. Several road safety issues have been identified with regard to the new facility and this review recommends some strategies to mitigate risks. Keywords: elevated U-turn, Level of Service, accident prone 1. INTRODUCTION Circumferential Road 5 (C5) is one of the major circumferential roads in Metro Manila and it connects the South Luzon Expressway in Taguig City to the north end of C5, the McArthur Highway in Valenzuela City and the North Luzon Expressway. Moreover, the C5-Kalayaan Avenue intersection is strategically located in the boundaries of Taguig City, Makati City, Pateros, and Pasig City which makes the said intersection congested especially during peak hours.

Figure 1.1 The C5-Kalayaan Intersection

C5

Kalayaan Ave.


The interchange configuration proposed by the Department of Public Works and Highways (DPWH) for upgrade of the C5-Kalayaan Avenue intersection was an underpass that would serve through traffic along C5. The underpass scheme is part of the two grade separation infrastructures: the C5-Kalayaan underpass and C5-Vargas-Lanuza overpass that cost P512-million. Consulting services for the construction supervision of this interchange projects had been awarded to private engineering firms in 2002 and detailed designs were already completed for implementation in 2004. The Metro Manila Development Authority (MMDA), however, submitted counterproposals to construct two (2) U-turn flyovers along C5 instead of the proposed underpass at C5-Kalayaan and the retention of the U-turn scheme at C5-Vargas and C5-Lanuza. This P350-million worth project was favored than the earlier DPWH’s plans. Construction of Phase I (Taguig side) commenced in February 14, 2008 and was completed on August 1, 2008; while Phase II (Pasig side) was started on December 2, 2008 and completed on April 17, 2009. Last May 6, 2009, President Gloria Macapagal-Arroyo inaugurated the twin elevated U-turns in C5. MMDA Chairman Bayani Fernando led the formal presentation of the finished project. The initial operational performance of the new facility based on MMDA reports are quoted below.

“Travel time along Circumferential Road 5 (C-5) has improved up to more than 85 percent only nine days after the Metropolitan Manila Development Authority (MMDA) opened its second elevated U-turn interchange at the intersection of C-5 and Kalayaan Avenue in Makati City.” “…that simulation tests and post-evaluation study at the C-5/Kalayaan Avenue intersection showed a dramatic increase in travel speed in the area, from the average 20.85 kilometer per hour (kph) in 2006 and 2007 to 38.84 kph, an improvement of 86.28 percent.” “…due to the improved traffic condition, vehicular volume in the intersection has also increased from 120,135 to 151,907 following the opening of the Phase 2 (north side) of the C-5/Kalayaan Urban Interchange on May 6.” “At the northbound lane of C-5, from Commando Link in Taguig to Lanuza, travel speed also increased from 28.85 percent to 52.89 kph and from 17.16 kph to 42.20 kph on the opposite southbound direction…” “At the eastbound, from Lawton, Taguig to Buting, average travel speed is now 28.03 kph from 17.93 kph and 38.84 kph from the previous 20.850 on the westbound portion.”

2. OBJECTIVES The objectives of this study are the following:

� To present an initial review of the completed U-turn flyover upgrade project for the C5-Kalayaan intersection.

� To examine miscellaneous vehicle inconveniencies and accident prone areas. � To recommend strategies for improving safety.

3. LITERATURE REVIEW The U-turn program is the closure of an intersection and the provision of U-turn slots for the diverted traffic. The left turn and or crossing through traffic affected by the closure of signalized intersection are re-directed via U-turn slots to ensure non-stop traffic flow along major road. The U-turn program is under the traffic management programs for Metro Manila and referred to as the “Big Rotunda Scheme” as shown in Figure 3.1. The MMDA had


implemented the program since June 2003 initially along Quezon Avenue and EDSA, then to Commonwealth Avenue, Marcos Highway, E. Rodriguez Avenue and Gil Puyat Avenue. With the implementation of the U-turn scheme, travel time has been reduced up to 10-20%. Results of a study by MMDA’s Traffic Engineering Center (TEC), as mentioned by Regidor (2004), support the claim of improved travel time. Uy et al. (2008) examined U-turn and compared it to the signalized intersection traffic system management considering fuel consumption and other factors such as duration, velocity, and RPM. Results of the study showed that U-turn promotes higher fuel consumption rates than signalized intersection scheme since the former has longer run duration and more frequent changes in maneuvers than the latter. Regidor (2004) cited and briefly discussed several design provisions related to the design of U-turns from different sources that include Department of Public Works and Highways, American Association of State Highway and Transportation Officials, Roads and Transportation Association of Canada, Traffic Engineering Handbook and U.S. Highway Capacity Manual (HCM).

Figure 3.1 MMDA’s Big Rotunda Scheme

(Source: http://www.mmda.gov.ph/trafprg.htm) 4. METHODOLOGY The procedures involved gathering of available data which are categorized as secondary type of data. Some differing assessments of a number of traffic engineers especially before and during construction of the elevated U-turn were taken into consideration. The on hand information gathered is then analyzed based only on applicable traffic analysis as well as qualitative analysis. The configuration of the elevated U-turn scheme is thoroughly examined. Some limitations such as length of vehicles that can pass the U-turn, evaluation of geometric design, possible collision points and other issues were identified. Then strategies for improving safety through physical improvements are recommended. 5. DATA COLLECTION Traffic volumes used in traffic analysis are obtained from MMUTIS Report and projected for the year 2015. Figure 5.1 shows the daily traffic (AADT) and peak hour volume (PHV) both in passenger car unit (pcu). The PHV is a critical traffic input and therefore it is usually used in the design of road projects.


The lay-out of completed U-turn flyover along C5 shown in Figure 5.2 is drawn based on photos obtained through site inspections.

Figure 5.1 Projected Traffic Flow

Figure 5.2 Present lay-out of C5-Kalayaan intersection with twin U-turn flyovers


6. ANALYSIS There is no actual comprehensive traffic study conducted for this review to obtain detailed information for an in-depth engineering evaluation since analysis of U-turn is not yet established. Moreover, even though the MMDA’s Traffic Engineering Center conducted a study on initial operational performance of the new infrastructure, their reports have not yet been subjected nor opened to unbiased peer review. The traffic accident data on the twin U-turn sections of C5 were not considered owing to the fact that few available records would not be adequate for an impartial assessment with regards to road safety. 6.1 Traffic Analysis An uninterrupted traffic flow along C5 results from the closure of signalized intersection. However, there are potential weaving problems as shown in Figure 6.1. These are examined and assessed applying HCM (2000) recommended weaving analysis. The details of the analysis are shown in Appendix A. The weaving segment will operate at LOS F during the peak hour which is described reflecting densities less than those identified since drivers expect and will accept higher densities on weaving segments than on basic multilane highway segments. Congestion in the weaving section would affect the conditions at the elevated section, the exit ramp and through traffic. The weaving segment density ranges from 48 to 52 pcu/km/lane. The weaving segment capacity cannot be determined from the given tables since the free flow speed used is 64 kilometers per hour. 6.2 Qualitative Assessment The configuration of the newly constructed U-turn slots along C5 to some extent is not similar to the typical design of U-turn slots due to its elevated scheme from the major road. The MMDA’s indication that U-turn slots program is a “Big Rotunda Scheme” or comparable to a roundabout would still be questionable if applied to this particular infrastructure since the U-turn was elevated and therefore defies the conventional design of roundabouts. A visual inspection alone of the elevated U-turn poses several issues regarding its geometric design. There are two uniform lanes in the approach ramp, elevated section, and the exit ramp. However, sharp curves as highlighted in Figure 6.2 are observed on the elevated section which are possible crash areas of vehicles. Table 6.1 discusses the different advantages and disadvantages that could be expected in the installed facility.

Figure 6.2 Sharp curves at the elevated U-turn


Figure 6.3 shows the identified possible vehicle crashes in the elevated U-turn segment apart from collisions that may also occur due to weaving and mistakes in maneuvering.

Figure 6.3 Possible collision points at the elevated segment

Table 6.1 Advantages and disadvantages of elevated U-turn

Advantages Disadvantages

1.) A stand alone facility would promote savings on personnel and equipment, including electricity since no traffic signal is required

1.) More accidents are likely to happen at merging area on the center and sharp curved u-turn (possible collision points are identified in the succeeding figure)

2.) Travel time and costs are increased for left turns and through traffic in both eastbound and westbound directions because of longer travel distance

3.) There is a turning limitation on the elevated U-turn especially for long vehicles

4.) In cases of accidents on the elevated segment of U-turn, a choke point scenario, there would be no alternative route for the vehicles

5.) Some tapering section of through lanes due to the column supporting the elevated U-turn may result to incidence of road crashes

6.) Structures elevated above the city streets scar the city visually and also contribute to increased air and noise pollution


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7. CONCLUSION This paper presents a preliminary review of the elevated U-turn project constructed as solution to the congestion problems experienced in C5-Kalayaan intersection due to sheer volume of vehicles passing along the major road – C5. Traffic analysis revealed that the weaving segments have LOS F, an indication of traffic problems in 2015. Qualitative assessments further disclosed that the disadvantages with regard to turning radius limitations, increase in road accidents due to weaving and a number of possible collision points, and also the negatively affected east or westbound vehicles disapprovingly outweigh the advantages of the facility. The facility has already been completed but physical improvements as well as traffic management may be explored and implemented to address the issues. 8. RECOMMENDATIONS The objective of road infrastructure upgrade project is to improve current traffic conditions and be able to sustain future traffic demands. One of the key measures for improved operational performance of roads is the decreased travel time in accessing the facility. However, fundamental rules on road safety should not be compromised alongside attaining improved efficiency. The recommended strategy to help mitigate traffic accident risks is to improve driver awareness of the U-turn flyover, impose speed limits especially at weaving sections, and provide more effective guidance for motorists through the use of signing and pavement markings. Future road projects should uphold and consider national and international standards on traffic engineering and management. In the world of professional practice, road project plans and proposals should be open to peer reviews and critiques to realize an effective solution to Metro Manila’s traffic problems.

ACKNOWLEDGEMENT

The researchers acknowledge the invaluable ideas and support of all faculties involved in this practical paper.

REFERENCES

Regidor, R. J. F, Economic and Technical Analysis of C5/Kalayaan and C5/Vargas-Lanuza, 2004

Uy, F. A. A., Vergel, K. N., Evaluation of Traffic Management Strategies Considering Fuel Consumption, 200__

U. S. Highway Capacity Manual, 2000 Metro Manila Development Authority, The Official Website of, http://www.mmda.gov.ph

microsoft word - easts 2009 c5-kalayaan rev

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