Chapter 1 Background
This proposal has been developed in response to a call for a proposal made by the Singapore Institute of Technology (SIT) to benefit the citizens of Singapore by identifying a local problem in the infrastructure sector. The team has decided to improve traffic safety in high-risk zones, more notably at slip road zebra crossings. According to the “Basic Theory of Driving Official Handbook, 9th edition”, The current markings available on the pedestrian crossings of Singapore include a deceleration lane dotted white lines, white zigzag lines and stop lines.
A member of this team who is an experienced traffic engineer of the Land Transport Authority (LTA), Iskandar Bin Khairuldin, has shared that Singapore faces high accident rates among road users. According to Budget Direct Insurance (2020), there were “7690 road accidents involving injuries”, and “fatality rate of 2.73 per 100,000 citizens is higher than London, Hong Kong and Tokyo”. This study has proven that Singapore has similar accident rates compared to other countries despite our size of population being much smaller.
The team then decided to narrow down to mitigating risk at slip road zebra crossings. Iskandar further states that he received feedback; questioning on safety at slip road zebra crossings. He shares that unclear markings at the pedestrian crossing is the main cause of collisions because it fails to alert inattentive motorists effectively; preventing them to react in time.
According to The Straits Times (Alkhatib, 2020), an inattentive driver had caused a fatal accident in February 2020 which took away a cyclist's life at a zebra crossing. Therefore, there is a need to address the high accident rates in Singapore; first by developing a solution to prevent such catastrophe from happening at a slip road zebra crossing.
LTA (2009) has claimed to have tested traffic calming markings (TrCM) at three different streets in Singapore. In the same report, it has mentioned that 10% of overalls speeds decreased. 64% of those surveyed have shown to have slowed down. In 2013, Iskandar was involved in an LTA project to mitigate accidents at Wilkinson Road/Crescent Road junction. Iskandar and the team decided to adopt TrCM along Wilkinson Road/Crescent Road road; there has not been an accident at the junction since this implementation.
According to numerous literature reviews, TrCM has successfully proven to be effective, ensuring that drivers slow down when they encounter the markings; reducing the risk of accidents. With such measures taken, secure and safe slip road zebra crossings can be developed in Singapore, thus ensuring the well-being of road users.
1.1 Problem Statement
An ideal slip road zebra crossing includes having motorists to react in an appropriate manner. The current markings on crossings are not visually captivating as it has failed to alert motorists in reducing their driving speed to check for pedestrians ahead, resulting in collisions. However, LTA has no plans to further improve the clarity of road markings.
The team aims to create an ideal slip road zebra crossing by adopting both TrCM and checkered markings. With striking and clear markings painted onto the crossings, it can reduce the risk of accidents and create a safe environment for road users.
This proposal aims to enhance slip road zebra crossings by implementing TrCM and checkered markings at the zebra crossing.
1.2 Purpose Statement
The purpose of this proposal is to convince LTA and inform the Traffic Police (TP) on the need to mitigate risk on slip road zebra crossings. Preventive measures can be done by implementing TrCM and checkered road markings onto the crossing to improve safety levels on the roads.
Chapter 2 Proposed Solution & Benefits (2-3 pages)
2.1 Proposed Solution
The team aims to mitigate risks on slip road zebra crossing by utilising and enhancing existing traffic markings by introducing TrCM.
Citing from LTA(2013), TrCM, or otherwise known as Dragon Teeth, are triangular road markings perpendicular to the edge of the carriageway often used at gateways to give the effect of road narrowing. As reported by LTA(2013) in an overseas conference report, the dragon teeth markings have been successful in visually changing motorists behaviours to travel at reduced speeds. It is also reported that the teeth are laid in pairs either side of the carriageway or a lane. The dragon teeth markings are currently widely used in countries such as Australia and the United Kingdom. Singapore has recently adopted this idea.
The team is proposing to implement TrCM onto existing crossings to create an ideal slip road zebra crossing. The figure 2.1.1 shows the proposed solution, as the TrCM will be placed at the start of the slip road, with interval distances between each markings, as the markings approach the zebra crossing. Additionally, the checkered markings will be placed at the sides of the zebra crossing, within 3 metres of the white band markings.
Figure 2.1.1 LTA standard on dragon teeth/traffic calming markings on
slip road zebra crossing
2.2 Benefits gained from traffic calming markings(TrCM)
The team has identified the key stakeholders to be the general public, LTA and Traffic Police (TP). With the TrCM implemented onto the slip road with pedestrian crossings, the overall risk of collision at the slip road zebra crossings will be decreased. This results in lesser casualties; ensuring a safer road for the general public.
TrCM will allow pedestrians to utilise the crossings without feeling anxious about getting hit by motorists. Drivers will benefit by being able to focus better and to react quicker; observing if pedestrians are approaching the slip road. LTA and TP will have lesser accidents to attend to.
As cited from a research journal (Montella, et al. 2011), implementing the TrCM will be more feasible as stakeholders are more likely to implement the solution as it has shown its efficiency in speed reduction while minimising installation cost. Based on Iskandar’s previous project, he has estimated that the proposed TrCM solution will also incur a lower implementation cost of approximately $1800 as compared to completely repaving an area of slip road ($50,000) to incorporate a new traffic-calming system.
2.3 Key stakeholders
All key stakeholders are expected to take measures for an effective implementation. As mentioned by Iskandar, LTA will be responsible for establishing the markings. LTA should also consistently monitor and maintain TrCM; ensuring that these markings are still working well.
Traffic Police Force(TPF) shall continue their role in enforcing regulations, investigating the causes and contributing factors when collisions appear, and at the same time educate the public that individuals are still responsible for their own safety. The general public should still remain alert and not rely solely on the markings.
Key stakeholders
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Effects
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General public/Road users
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LTA & TPF
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Table 2.2.1 Effects on key stakeholders
Key stakeholders
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Plan of Action
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General public/Road users
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LTA
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Form a team to draw the markings on the slip road
Execute follow ups after implementation
Request for statistics on accidents from TP after implementation for improvement measures
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TPF
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Updates LTA about accident rates and causative factors to accidents after implementation (Collision due to drink-driving, speeding etc.)
Educate the general public to not rely solely on the road markings
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Table 2.2.2 Actions that is required to implement traffic calming markings
Chapter 3 Evaluation
The team has identified a total of 3 potential challenges that needs to be addressed, to implement the traffic calming effectively.
3.1 LTA design standards
Challenges:
The first challenge traffic calming markings(TrCM) also known as dragon teeth marking faces is complying to the LTA design standards. Figure 3.1.1 shows the distance required from LTA to implement the dragon teeth at a straight road. TrCM is set to be painted with a decreasing interval over a distance of 53m.
Figure 3.1.1 LTA standard on dragon teeth/traffic calming markings
Figure 3.1.2 shows a diagram on slip road zebra crossing in Singapore which is typically a left filter off traffic lane with a zebra crossing facility at its end. To implement the LTA standard sets of triangular markings in the decreasing intervals from 8m to 2m is not achievable. The lanes of slip road zebra crossing is shorter than 53m.
Figure 3.1.2 Standard slip road with existing markings
The second challenge faced is caused by existing markings on the slip roads pedestrian crossings which includes white zig zag lines and white dotted lines. These markings increase the difficulty to adopt the TrCM due to space constraints.
According to the TrCM LTA standard (2009) in Figure 3.2.1, it shows that dragon teeth have a base of 0.5m and a vertical height that will vary; as long as there is a minimum distance of 1.5m between the two opposite sides. Also mentioned in the standard, all slip road zebra crossings are wider than 2.7m. The current zig zag markings that are now on the left side of the crossing will provide very little space for TrCM; zig zag markings that are on the left side take up more space than the white dotted lines on the right side.
Figure 3.2.1 Dimensions of dragon tooth
Solution: Improvise
To have an effective implementation yet still meeting the standard from the LTA, the team has decided to paint only one dragon tooth on the left side of crossing shown in Figure 3.2.2. This improvisation can resolve both challenges of distance and space constraints.
Figure 3.2.2 Left side of the road to have 1 dragon tooth
3.2 Visual appeals
Challenges:
The third challenge is also caused by the current markings because it increases the chances of drivers ignoring the new implementations marking. Existing markings overshines the TrCM when painted along the same path as the existing marking. Figure 3.3.1 shows a model of the current markings and TrCM, when painted at a slip road zebra crossing. As shown, the dragon teeth are barely seen.
Figure 3.3.1 Slip road zebra crossing with white TrCM (not drawn to scale)
According to a research journal (Lee, et al. 2013), a study was conducted on the effect of traffic calming markings to driving speeds of high risk drivers. The study showed that there was a significant decline in driving speeds, but it was concluded by the authors that colour was an aspect that could be looked into, to improve the results further.
Solution: Yellow TrCM & Yellow checkered markings
Therefore, our team decided to paint the traffic calming markings, TrCM in yellow. Figure 3.3.2 shows the same diagram as above but with the dragon teeth painted in yellow. TrCM is so much more visible and striking, to ensure that drivers will focus on it.
Figure 3.3.2 Slip road zebra crossing with yellow TrCM (not drawn to scale)
To further improve the visibility of road markings on the slip road zebra crossing, the team decided to add in yellow checkered marking; similar to the one that can be found in pedestrian crossing at school zones.
To integrate the yellow checkered markings can be an issue as the top management might reject the idea of adopting it onto slip road zebra crossing. According to the LTA standards(2014), yellow checkered markings are designed for road humps or any form of elevation in a curved road; to inform drivers about the hazards ahead. However, a slip road zebra crossing is flat with no raised bumps like the crossings at the school zone.
Therefore, the team decided to propose that yellow checkered marking is to be adopted at one side of the road, filling up the 3m empty space.
Figure 3.3.3 Yellow checkered markings between stop line and crossing
To conclude, the team has decided to implement the dragon tooth in yellow together with yellow checkered markings; enhancing the visibility to motorists. Drivers will then take note of the markings, paying close attention ahead and to react properly by slowing down naturally. Thus, reducing overall collision risk.
Figure 3.3.4 Final TrCM implementation plan
3.4 Feasibility of solution
Given the benefits and constraints of our solutions, the proposed Traffic Calming Markings(TrCM) will be a scaled down version of the TrCM triangular markings to fit within the left slip road. These markings will be painted at intervals of every 5 metres within the white dotted lines and in between the standard distance of existing white zig zag lines.
Additionally, the dragon teeth will be painted yellow instead of standard white that has been used previously. The colour contrast of yellow would be more visually captivating to motorists as they react promptly to yellow road markings. The effect colour to reaction of motorists is evident with the currently existing markings which for example, has been used to distinguish bus lanes with main traffic lanes. The proposed yellow dragon teeth markings aims to influence motorists to slow down as they approach the markings.
Figure 3.4.1 Spacing measurements of Proposed Yellow TrCM with existing markings
(not drawn to scale)
Figure 3.4.2 Yellow checkered markings in between yellow/black painted flashing beacons
Figure 3.4.3. Yellow TrCM painted along slip road towards YCM at zebra crossing
The proposed yellow TrCM at slip road zebra crossings will supplement existing road markings that have been the standard road markings seen on our public roads for a long time. Its purpose is to instill visual perception and trigger motorists’ awareness of the need to reduce their speed .
Painting yellow checkered markings at the white band of the zebra crossing will visually enhance the pedestrian crossing area, creating a gateway effect, together with the pair of yellow/black painted flashing beacons. When the flashing beacons turn on at night time, both yellow blinking lights from the flashing beacons and the yellow checkered markings will help to illuminate the zebra crossing area further and increase motorist alertness to stop and watch out for pedestrians crossing.
4.0 Methodology
The methodology of this proposal is based on both primary research and secondary research.
4.1 Primary Research
The primary research for this project was in the form of an experience by an LTA traffic engineer, Iskandar Bin Khairuldin, a member of this team. As a traffic engineer, part of his job scope is to resolve public feedback involving traffic issues. While encountering public feedback, Iskandar and his colleagues realised that feedback towards road slip accidents are becoming more prominent. However, there was no new solution available for them to combat this issue as road markings and road signalling devices are already in use on roads.
Interviews by two members of LTA were also conducted. One of them includes Norashikin Mohammed Ali, the manager of Traffic Scheme Design Development Division (TSDD) of Traffic and Road Operations. Another staff that we interviewed was Ng Yew Wei, Joshua, the principal engineer of the Road Safety Engineering Division (RDSE) of Traffic and Road Operations.
4.2 Secondary Research
The main source of secondary research is a review of a series of articles. Some of which included a report of an overseas conference conducted by LTA and research journals detailing on the effects of TrCMs on motorists. A handbook published by Traffic Police titled “Basic theory of driving” was also used to gather information about existing road markings.
Chapter 5 Concluding Statement (
