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Category Archives: Highway Engineering
On bike lanes contributing to safer roads
Do bike lanes make roads safer? There are obviously mixed reaction to this question especially if you look as social media. If we are level headed about this topic and look at the evidence out there, the answer is yes. But there can be caveats as we try to contextualize in the local setting. The formal studies so far are in countries where the drivers arguably more disciplined than ours here in the Philippines. Driver behavior, after all, is a major factor for road traffic safety. Here is a good article for reference in the discussions and arguments for bike lanes:
Tu, Maylin (November 5, 2024) “How Bike Lanes Slow Drivers and Save Lives,” Next City, https://nextcity.org/urbanist-news/how-bike-lanes-slow-drivers-and-save-lives [Last accessed: 11/10/2024]
To quote from the article:
“Bike lanes with physical delineators (cones or bollards) were more effective than paint-only lanes at calming traffic, echoing a popular mantra for bike activists: “Paint is not protection.” (The lanes were not protected, however, because drivers could drive over the delineators.) For vehicles turning right, top speeds were reduced by 28% and average speeds by 21%. Paint-only bike lanes slowed driver speeds by up to 14% and drivers going straight slowed down by up to 8%…
The study adds that pop-up bike lanes are a cost-effective solution for studying the effects of more permanent solutions — after all, you could just borrow the traffic cones. A city could quickly implement pop-up or temporary infrastructure. Then, armed with data and community feedback, they could invest in making the changes permanent.”
The article also points to a technical paper or scientific article on the traffic calming effect of bike lanes. Here is the link to the article published in the Journal of Urban Mobility: https://doi.org/10.1016/j.urbmob.2024.100071
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Congestion due to flyover construction: Tagaytay-Nasugbu Road – Part 2
I showed photos of the construction of an overpass along the Tagaytay-Nasugbu Highway coming from Tagaytay in the previous post. This time, here are some photos taken along the opposite direction.
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Congestion due to flyover construction: Tagaytay-Nasugbu Road – Part 1
There is significant traffic congestion along the Tagaytay – Nasugbu Highway due to the construction of an overpass along the highway at its junction with the Tagaytay – Mendez Highway.
Was there a need for a flyover here? Otherwise I would suggest instead a set of good old-fashioned traffic signals and geometric improvements to the intersection.
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Technical sessions at the TSSP 2024 Conference
I am sharing here the latest draft of the technical sessions for the 30th Annual Conference of the Transportation Science Society of the Philippines (TSSP). The conference will be held in Iloilo City this coming September 13, 2024.
I will share the draft program for the morning plenary session in the next post.
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Skyway to the south
Instead of going via C5 and then SLEX en route to Tagaytay last week, we opted to take the Skyway via Quezon Avenue. The travel was smooth between 6:30 AM and 7:30 AM maybe because it was a Thursday and regular classes have not yet resumed (i.e., less trips). Note the counter flow lane adjacent to the median? This is implemented likely due to the experience of heavier traffic along the northbound (Metro Manila-bound) direction during the mornings. I wonder if the reverse is implemented in the afternoons/evenings.
Note that there was more traffic as we traveled between Makati and Muntinlupa. The traffic represented commuters residing in the south and traveling to Metro Manila for work purposes.
Article share: Planners’ Complicity in Excessive Traffic Deaths
Here is a recent article on safety and the involvement on traffic engineers from Todd Litman:
Source: Planners’ Complicity in Excessive Traffic Deaths
Let me note here about the interchangeability of the terms ‘traffic engineer’, ‘transportation engineer’ and ‘planner’. This is important to contextualize who is actually complicit or involved or responsible particularly in the Philippine setting. Too often and too quickly, traffic engineers or even civil engineers (in general) are blamed for traffic deaths or flaws in road designs. Disregarded is the fact that, as the article mentions, of the two major elements of travel – distance and speed – distance is often determined by the plans and designs of non-engineers. These are planners, or to be accurate land use planners, many of whom are architects by profession. We also want to differentiate between traffic engineers and highway engineers, who in the Philippine setting are actually quite different. One common thing about many of them is that they are slow to adopt progressive ideas or concepts of road planning and design such as complete streets and road diets. The outcome of this stubbornness is the specter of road crashes that lead to fatalities and serious injuries. But then they are not solely to blame or who should take responsibility for the atrocious road safety situation. The ‘distance’ component of travel is very much a product of land use planning and land development as practiced in our country. For many if not most developments, architects and planners are the ones who call the shots for the roads and transportation in the proposals. Traffic engineers are involved later and if not progressive complicates the situation regarding safety. Thankfully, some local government units are becoming progressive and are more mindful of development proposals including implications to road safety. Hopefully, many things will change among those involved so we can improve travel safety.
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Lower speed limits may not slow drivers, a before-and-after study shows
I am sharing this article on drivers not reducing their speeds after speed limits have been lowered along certain roads. My first reaction after reading the article is that it is that perhaps in the US case, the after study was conducted quite early and before people have become aware, understood and adjusted to the lower speed limits. The responses or reactions to lower speed limits (particularly those posted or on signs) may vary among cities and countries. In the Philippines, where drivers and riders appear to be oblivious to speed limits, other interventions may be required including some types of traffic calming devices. This is very much a concern particularly in school zones where children are exposed to the risks of being run over by motor vehicles speeding along the roads and not minding the speed limits in the area.
Here is the Research report:
Source: Lower speed limits may not slow drivers, a before-and-after study shows
Article share: on using optical narrowing to make streets safer
I’m sharing this interesting article on the concept and application of optical narrowing to improve road safety:
Erfurt, E. (September 15, 2023) “How to Use Optical Narrowing to Make a Street Safer,” Strong Towns, https://www.strongtowns.org/journal/2023/9/15/how-to-use-optical-narrowing-to-make-a-street-safer?fbclid=IwAR147sLmkMBwStj51FR1ehNcVsi1YpN70etrpGOwv9DHL4ZhJIDLzP8cb1s [Last accessed: 3/14/2024]
To quote from the article:
“We all perceive the world around us through visual reference points. As we look around, we are next to the wall, or across the street from the bank—in other words, we position ourselves relative to what we see. This is even more apparent when we are driving: you may perceive yourself as behind another car, or between the lines on the road.
Drivers make decisions based on these visual cues. If things are further away, we are more inclined to speed up. The auto industry has marketed this as the “freedom of the open road,” and the visual of a wide open road is paired with the acceleration of the car. If no one is near and all the fixed objects, such as curbs and buildings, are far away, then the perception is that we have less risk and we throw caution to the wind.
If things are closer, we are more inclined to slow down. Our natural inclination is caution and possibly a little bit a fear that we may hit something. When you drive on a street where the lanes are a little narrower, or the buildings are at the back of the sidewalk, our reference points become closer. We have to focus, and in an abundance of caution we drive slower. The perspective is that we have more risk, and we pay more attention to counter that risk.”
This would be a good quick reference to planners and engineers who are involved in road safety, particularly in applying complete streets concepts to reduce the risk of crashes along streets.
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More than just painted lines – good practice examples of bike lanes
I’m sharing this article on the best bike lanes in the United States:
Holbrook, A. (February 12, 2024) “The 5 Principles That Make America’s Best Bike Lanes: A Lot More Than Painted Lines,” Velo, https://velo.outsideonline.com/urban/urban-gear/five-principles-the-best-bike-lanes/ [Last accessed: 2/15/2024]
This is a follow-up on an article on the best new bike lanes or bikeways that I shared earlier. This article features an interview of the author of the previous article about what features distinguish these bike lanes over others that have been implemented. Definitely, bike lanes should be designed beyond the usually painted lines that offer little protection to cyclists.
Here are examples of bike lanes in the Philippines:
Painted bike lanes along Ortigas Avenue Extension, Cainta, Rizal
Protected bike lane along Katipunan Avenue (C-5), Quezon City
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Zamboanga’s first flyover
We passed by the construction site of Zamboanga City’s first flyover at the intersection of the Pan Philippine Highway (AH 26) and Veteran’s Avenue. I recall there was a lot of pressure from DPWH for the city to approve its construction. The previous mayor didn’t want to approve the project because the perception was that it was not required and there were other options to consider before a flyover was to be constructed. However, many people including the then congressman and now mayor probably thought the flyover would be the solution to the congestion experienced at the intersection. Add to that the perception that the flyover is also somewhat a symbol of progress.
We won’t know until its completion and the ‘normalization’ of traffic in the area to determine whether the flyover has ‘solved’ traffic congestion in the area. The problem with this approach to ‘solving traffic’ is that it is usually a short-lived alleviation of a symptom of the real problem, which is transportation. Zamboanga City has deferred rationalization of public transport routed despite analysis and plans pointing to a streamlined and optimized transportation system if this was pursued. The City commissioned a Transportation and Traffic Management Plan Study in the previous administration but the plan and its recommendations have been shelved, another example of such being casualties of a change in administration of an LGU.
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Caught (up) in traffic 