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Category Archives: Traffic flow
On car following
We teach our students about car-following theory and applications in our transportation engineering courses at the undergraduate, graduate and post-graduate levels. This is an important part of traffic flow theory and essential in understanding and modelling traffic flow/ behaviour. Among its applications is in the development of simulation models such as those that are now commercially available like VISSIM and CUBE-DynaSim and the older but still very useful TRAF-NetSim. Car-following theory allows for a more accurate simulation of real-world traffic behaviour considering the many parameters describing traffic flow as well as the assumptions that need to be in place for various scenarios.
Here’s an interesting article that’s basically about car-following, specifically mentioning the proper (ideal?) spacing between vehicles and how such discipline can lead to less congestion along our roads.
Simon, M. (2017) Math says you’re driving wrong and it’s slowing us all down, Wired, https://www.wired.com/story/math-says-youre-driving-wrong-and-its-slowing-us-all-down/?CNDID=37243643&mbid=nl_121517_daily_list3_p4 (Last accessed: 12/17/2017).
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The need for speed (limits)?
My social media newsfeed regularly contains updates being posted by various entities about transport and traffic in Metro Manila and across the Philippines. Among those I regularly see are posts on road safety and interesting to me are the frequent posts on legislating speed limits at the local level. These are in the form of city or municipal ordinances that are supposed to strengthen, supplement and/or clarify speed limits that are actually already stated in the road design guidelines of the Department of Public Works and Highways (DPWH). These limits apply not only to national roads but to local ones as well. However, their effectiveness may be limited or reduced by the absence or lack of signs, markings and, most importantly, traffic law enforcers who are supposed to monitor traffic and apprehend those violating rules and regulations.
While there is a need for defining and clarifying speed limits perhaps in the form of local legislation, I believe the more urgent matter is the implementation and enforcement of laws. It has often been mentioned that we already have so many laws, rules, regulations and the truth is we do, and may not need more. One really has to go back to the basics in terms of enforcing these laws and that means enforcers need the knowledge and tools to be effective in their work. There is an opinion that many enforcers are not knowledgeable about many rules and regulations and therefore are prone to just focus on a few including violations of the number coding scheme, truck bans and the much maligned “swerving”. You do not often seen apprehensions for beating the red light, beating the green light (yes, there is such a violation), speeding, or “counter-flowing” (or using the opposing lane to get ahead of traffic in the correct lanes). There are also turning violations as well as those involving vehicle (busted tail lights, busted headlights, busted signal lights, obscured license plates, etc.). More recently, there are anti-drunk-driving laws that also urgently need proper implementation.
I think the current work that includes sidewalk clearing operations and anti-illegal on street parking of the Metropolitan Manila Development Authority (MMDA) is one good example of going back to the basics. These address the necessity of clearing space for both pedestrians and vehicles; space that have been constrained by obstacles that should not be there in the first place but so often have gotten the blind eye treatment. Going to the “next level” though requires tools such as speed guns, high speed cameras at intersections, and instruments for measuring blood alcohol levels in the field (breath analyzers). And these require resources for acquisitions as well as capability building in the form of training personnel to handle equipment. No, I don’t think we need more laws, rules and regulations. What we urgently if not direly need is their proper implementation to effect behavior change that will improve both safety and the flow of traffic.
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Tacloban’s one-way traffic scheme
I was in Tacloban City last month and got to meet former participants to our training program who are working for their Traffic Operation Management Enforcement and Control Office (TOMECO). Among the topics of discussion was the traffic scheme for the central business district (CBD). Last year, the city had implemented a one-way traffic circulation scheme for the CBD as shown in the following map in the traffic advisory released by the city:
The city had to ease up on the one-way scheme, retaining it for the northwest-southeast directions and reverting to 2-way flow for the northeast-southwest directions. This decision was apparently due to the feedback the city got from various stakeholders about travel times and distances becoming longer due to the one-way scheme. This needs to be verified by collecting data pertaining to typical routes taken by vehicles, private and public utility, in order to get from an origin to a destination (e.g., from home to school). This can be simulated or estimated using field data (travel time surveys). We intend to use both as we make an assessment of the scheme and formulate recommendations for the city.
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On one way schemes
A proposed one-way scheme for EDSA, C-5 and Roxas Boulevard raised not a few eyebrows among transportation and traffic professionals. While it seems to some that the three major thoroughfares are parallel or can be paired in such a way that EDSA can be one-way southbound, and C-5 and Roxas Blvd. can be one-way northbound, it is not as easy at it seems because these arterial carry a heckuva lot of traffic compared to the roads they are being compared to (New York?). The road network layout is also quite different. We have a circumferential and radial road network as the backbone of road-based transportation. A one-way scheme could be more effective if we had a grid type network where you have several pairs of roads that can be designated as one-way streets.
Take the case of Tacloban City, whose central business district has a grid-type network with intersections relatively closely spaced. The city implemented a one-way scheme as shown below:
Note the pairs of roads designated for one-way flow. These basically make for efficient traffic circulation provided the capacities of streets and intersections are not significantly reduced by factors such as on-street parking and other roadside friction. This can be achieved in various places in Metro Manila where streets are similarly laid out and there are multiple pairs to promote good circulation. Makati, for example, has many one-way streets in its CBD, and these are also in pairs. While having high capacities, EDSA, C-5 and Roxas Boulevard just does not have the closely spaced intersections to effect efficient circulation. In fact EDSA (or C-4) and C-5 are arterials that function to distribute the traffic carried by radial roads such as Roxas Blvd., Shaw Blvd., Commonwealth Ave, Aurora Blvd., etc.
A better option is to focus on improving road -based public transport by setting up high capacity, express bus services with exclusive lanes. These may not necessarily be full Bus Rapid Transit (BRT) systems but requires a drastic reduction and restructuring of current numbers of buses along EDSA and their deployment along corridors like C-5 and Roxas Blvd. Express means longer intervals between stops (hint for EDSA: express bus stops coinciding with MRT-3 stations), and increased travel speeds made possible by exclusive lane(s). This could have been piloted during the APEC meetings in the previous administration where 2 lanes for each direction of EDSA were appropriated for APEC vehicles. These lanes could have been used afterwards for a BRT (-lite?) system and what could have been an pilot could have also provided an appreciation or “proof of concept” for BRT in Metro Manila that we could have learned a lot from.
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Why do we need to reduce speeds?
A common observation made of Philippine drivers is that they seem to hesitate from slowing down even at hazardous locations or situations. Note, for example, vehicles approaching an intersection and you will observe that many if not most will not reduce their speeds. Most guilty for me are motorcycle riders who tend to maneuver and even speed up instead of slowing down for a safer approach. Slowing down (i.e., reducing one’s vehicle’s speed) is actually a no-brainer and something that is explicit in any country’s traffic rules and regulations and driver’s handbook.
I saw a lecture on why reducing speeds are important. This is not just from the specific perspective of safety but is explained in favor of mobility and quality of life. Here’s the lecture:
Reducing speeds for better mobility and quality of life by CarlosFelipe Pardo
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Responding to the transport impacts of road crashes
Last March 9, traffic was terrible along Marcos Highway and roads connecting to it including Imelda Avenue and Sumulong Highway due to a truck that slammed into the scaffolding of the Line 2 Extension across the Sta. Lucia Mall, and barely missing the newly constructed column supporting the girders and elevated tracks of Line 2.
[Photo not mine but sent by an officemate who was glad to have taken his motorcycle that day instead of commuting by car.]
Following are comments I captured from Waze as I tried to get information about the traffic situation:
It is very clear from travelers’ comments that most were frustrated and many were angry about what seemed to be a very slow response from authorities in clearing the crash site and getting traffic to move faster. I myself wondered how a crash like this with its impacts manifesting in severe congestion along major roads was not dealt with as urgently as possible by so many entities that were not without capacity to act decisively. The front liner should have been the Metropolitan Manila Development Authority (MMDA) and there were at least four local government units directly affected by the congestion: Pasig, Marikina, Cainta and Antipolo. Surely, these LGUs could have done more if the MMDA couldn’t, in order to resolve the problem? If the availability of heavy equipment was an issue, weren’t there available equipment from Line 2 contractor, DMCI, or perhaps from the construction sites nearby (Ayala is constructing a huge mall near the area.)? Surely, they could lend a payloader or mobile crane that can remove the truck or at least help unblock the area?
I finally decided to turn back and work from home instead that day. Later, I learned that authorities had to stop traffic along Marcos Highway around 11:00 AM in order to tow the truck and clear the area for traffic to normalize. I hope this serves as a lesson in coordination among government entities and that future incidents like this will not results in a “carmaggedon” like Friday’s congestion. One thing that also became obvious is that travelers passing the area are all dependent on road-based transport and the primary reason why a lot of people were affected by the crash. The expanded operations of the Line 2, whenever that will be, will surely change transport in these areas and for the better.
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The Tagaytay transportation predicament
The title of this article is actually a bit tame and on the diplomatic side of trying to describe transportation and traffic in this city that was once relaxed a retreat for many. I had wanted to end February on a good note and so I decided to defer posting this until March.
We used to frequent Tagaytay and liked spending some rest and recreation time there to the tune of being there almost once a month at one time. Needless to say, at the time travel to Tagaytay from our home in Antipolo took us only about 2 to 2.5 hours excluding our usual stop at Paseo in Sta. Rosa, Laguna. We liked the city so much that we even considered making it a second home; even inquiring and looking at properties there.
Fast forward to the present and it has become an excruciating travel with the highways leading to the city already congested. It didn’t help that when you got there, you also had to deal with serious traffic congestion. This started not a few years ago when the city approved developments by major players including Robinsons, SM and Ayala. The developments by SM and Ayala proved to be the backbreakers with Ayala coming up with the first mall in the city and SM operating an amusement park beside its prime acquisition that is the Taal Vista Hotel. Now, there is another mall under construction by Filinvest and right at the corner of the rotonda where the Aguinaldo Highway terminates.
Vehicles queue along the Tagaytay – Nasugbu Highway towards the Rotonda where Tagaytay traffic enforcers attempt to manage traffic but appear to create more congestion instead.
More on Tagaytay soon…
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First call for papers for the TSSP 2017 conference
The first call for papers for the 24th Annual Conference of the Transportation Science Society of the Philippines came out last Wednesday, Feb. 15:
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More congestion along Ortigas Avenue Extension?
There are two malls currently under construction along Ortigas Avenue Extension – SM East Ortigas and Waltermart Taytay. Nearing completion is the SM East Ortigas, which looks like a very big mall. It is the former Ever mall beside Riverside Subdivision and close to one of DMCI Homes’ first developments. It will open on December 2 and there are already a lot of promotional tarps announcing this along major roads including C-5, Felix Avenue and, of course, Ortigas Avenue.
Waltermart is further up towards Tikling Junction. These two are actually from the same mother company SM, which has somewhat diversified its retail business so it now includes the SM malls, Savemore, Waltermart and the newly minted S-Mall. These two are sure to generate a lot of traffic and cause more congestion with the SM East Ortigas already in an area where Ortigas Ave. Extension is regularly congested. I am not aware of any studies conducted with respect to this mall but I assume there is a transport impact study somewhere. Personally, I would ask SM to look into the case of SM Novaliches for something sort of a solution to the traffic problem right in front of the mall. Quirino Highway is widest along the section where SM Novaliches is, with the mall providing a very generous setback to accommodate multiple lanes for traffic to flow smoothly at least in front of the mall. That seems possible with SM East Ortigas especially since there is practically only 2 lanes for the westbound direction of Ortigas Ave. Ext. at this area.
Waltermart is a different thing because it is in an area where there is generally no congestion along Ortigas Ave. Ext. I also assume there is a traffic study somewhere providing traffic management schemes or alleviation measures in case congestion occurs due to the mall and its high density residential development component (it is part of a complex called “The Hive”).
I am speculative about the expansive lot vacated by Mitsubishi Motors beside the Panasonic complex. I wonder if any of the big developers are acquiring it and perhaps developing it into a major mixed use project. There is also the lot where Consolidated Tobacco used to be just across Countryside Subdivision and close to SM East Ortigas. Such future developments require careful study for its transportation impacts and the Municipality of Cainta should take a proactive stance for major developments that will generate a lot of traffic. Ortigas Ave. Ext., even after some widening, remains as a road with high potential and regularity for congestion. Only a mass transit system can probably decongest it but that will take some time to realize.
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Some relief due to the number coding adjustments?
A friend asked me about my commute after the Metropolitan Manila Development Authority (MMDA) had implemented a tweak in the number coding scheme. To those not familiar with the recent adjustments to the Unified Vehicular Volume Reduction Program (UVVRP) or more popularly known as the number coding scheme, the MMDA has recently eliminated the window that was applied to many roads. The 10:00 AM to 3:00 PM window is no more and the MMDA also extended the coding period to 8:00 PM from the old 7:00 PM lifting.
My observation from my personal experience commuting in the mornings between Antipolo and Quezon City is that my travel times have somewhat improved. After Undas, I have enjoyed travel times of 45 minutes to 1 hour during the same morning periods when I choose to travel. This has improved significantly from the 1.5 hours I had spent prior to the adjustment. My usual route was mainly through Marcos Highway so perhaps its not just the coding aspect but also the fact that much of the construction work for the LRT Line 2 Extension have been completed and there have been less obstructions due to this project between Masinag and Santolan. My homebound trips seem to have improved too for the same reasons although not as significant as my morning commute. Another friend has similar observations and is very happy about the big improvements he says he now enjoys considering he has even longer commutes between Antipolo and Manila (Intramuros) or Makati (Gil Puyat).
But generally speaking, is it possible that there are significant positive impacts of the tweak in the number coding scheme? My assessment is that it is very possible and very likely especially if we see it from the perspective of vehicle trip reduction due to the adjustments made in the restraint policy. The number coding scheme is a travel demand management (TDM) measure designed to reduce vehicle traffic through vehicle use restraint. By introducing the coding window many years ago, the restrictions to vehicle travel were in effect relaxed and that encourage more people to use their cars.
The elimination of the coding window means people could not move their times of commute to later than 7:00 AM or earlier than 3:00 PM. It meant people whose vehicles were “coding” had to leave (forced?) early and go home late. Extending the coding period to 8:00 PM probably was probably a back-breaker to many people. And then the difference now compared to the 1990s and decade after that is the availability of the more reliable Uber and Grab vehicles that many car-owners had no option to use before. I’m not a psychologist but perhaps such factors have led to an improvement in traffic conditions. How long this would last shouldn’t be so difficult to tell given the experiences in the past and the fact that population and vehicle ownership continues to rise. Perhaps a year or two if no significant improvements in transport (e.g., mass transit projects) happen.
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Starting November 14, the MMDA is also supposed to be clamping down (read: stricter implementation) on the motorcycle lane policy along EDSA, C5, Commonwealth and Macapagal Blvd. I’m not so sure how they will be doing this as enforcement along the stretches will require a lot of manpower.
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Caught (up) in traffic 