Home » Traffic flow
Category Archives: Traffic flow
Someone shared a post about a traffic scheme they will be implementing along Julia Vargas Avenue in Pasig City. The proposal is for the avenue to have a high occupancy vehicle (HOV) lane where vehicles with 4 or more occupants are to take one lane and all other vehicles the other. I am not entirely sure about the objective other than to promote high occupancies for vehicles. However, it would be nice to see how travellers will be behaving (e.g., complying) and how Pasig (with MMDA?) will be enforcing this scheme.
This is what a segment of Julia Vargas currently looks like with 2 wide lanes designated for motor vehicles (separated by the solid yellow line) and one narrow lane for cyclists (adjacent to the shoulder):
The intent is good but as a major link the scheme can be quite confusing especially for those who are not necessarily frequent users of this road. I assumed the yellow line was painted by the DPWH but it seems it was by Pasig. Perhaps they should have removed the old markings? Or maybe better if they rationalised the carriageway width to accommodate 3 lanes for motor vehicles and 1 wider lane for bicycles? From the photo above, it appears to me that it is possible to have 2 narrow lanes for general traffic and one wider lane for HOVs (in this case defined as having 4 or more occupants) and public utility vehicles. This configuration maximises the capacity of the road while having a the “best” lanes allocated for HOVs and bicycles.
I wish them success on this social experiment. Perhaps there can be valuable learnings from this including the need for connectivity to other links as well.
We begin February with a post on a road that’s becoming more popular as a major (as opposed to alternate) route to Bonifacio Global City (BGC) and Makati CBD – Circumferential Road 6. I took the following photo at the approach to the Nagpayong Bridge that is current has only 2 lanes (1 per direction). Another bridge is being constructed along the existing one that will increase capacity for the Pasig River crossing to 2 lanes per direction. This is similar to what was done to the Barkadahan Bridge crossing the Manggahan Floodway in Taytay, Rizal.
The volume of road vehicle traffic is steadily increasing along C-6. The adjacent land use offers a lot of potential for development (hopefully planned) that will feed more traffic along what will become a major thoroughfare in the near future. The land I am referring to are the reclamations on the side of Laguna de Bai along C-6 that are under the jurisdiction of Taguig and similar developments on the opposite side on what was once swampy or marshlands. One wonders if Taguig has a plan for all this or if the city is turning a blind eye and just letting developers do what they want. Most seem to be residential subdivisions and industries-related with a sprinkling of mainly small to medium-sized commercial developments.
Again, I think national and local governments should consider making this a public transport corridor by introducing formal public transport in the form of a scheduled bus service stretching from, say, Bicutan Interchange to Taytay Public Market. The demand along this corridor is steadily rising and only a better connection to C-5 limits an even steeper increase in traffic volume along C-6. The time is now in order to condition commuters about the system and to the unwanted congestion experienced along major roads in the metropolis.
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).
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.
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.
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.
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