Appropriate traffic calming device for roads in Sri Lanka

INTRODUCTIONTraffic calming is a device for achieve the goal of reducing vehicle speed and same time improving safety and enhancing quality of life of both non motorized road users as well as neighborhood residents. This includes traffic education, enforcement and engineering so called as three E’s. Under the education part, it involve physically alerting and compelling the drivers to slowdown by using physical and visual changes of road texture and road environment or by getting direct alert through road signs. This educates the motorist and gives the indication to reduce thespeed within the approaching area. By having speed limit signs, on spot traffic control authority (Police) involvements, speed detecting automated camera systems or vehicle activated traffic signal control systems it can be enforced motorized to reduce thespeed at particular point. Speed humps, curb extensions, chicanesand road narrowing’s are the engineering component of traffic calming device.

OBJECTIVEThe aim of this study is, to identify what are the traffic calming devices use in Si Lanka and how they worked in roads and out of these which are the most appropriate devices for roads in Sri Lanka.

LITERATURE REVIEWAbout history of traffic calming device in UK,‘’Traffic calming was first introduced into the UK with the 1865 Red Flag Act. This restricted vehicle speeds to about 4 mph, by requiring a pedestrian to walk in front of the moving vehicle. The Red Flag Act was repealed in 1896, allowing vehicles to

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travel at 12 or 14 mph, depending on the local byelaws. In 1903 the Motor Car Act raised the limit to 20 mph, and in 1930 the 20 mph limit for cars and cycles was abolished. In 1934 a limit of 30 mph was introduced in built-up areas, but other roads had no speed limit until a national limit of 70 mph was introduced in 1965. Speed limits of 40 mph were introduced on some roads in 1960. In 1990, 20 mph zones were allowed, as long as suitable traffic calming measures had been installed to ensure speeds reduced to 20 mph or less. Traffic calming has so far usually been implemented by installing highway engineering measures, which do not influence the driver’s ‘state of mind’, but physically restrict the manner in which the vehicle is driven’’Source: Local Transport Note 1/07, March 2007 (by Department of Transport, Northern Ireland)

www.tsoshop.co.uk

According to above document, this concept is old as 1800’s and restrict the speed as low as 4 miles per hour. This is match the vehicle speed exists in that period. When moving to present situation same document explain it as,“Traffic calming is a useful way of controlling drivers’ speeds where speeds are either excessive and/or inappropriate for the type and use made of a road. Justification for installing trafficcalming is often based on improving safety by reducing accidents.Whilst the number of accidents on residential roads is often relatively low, and usually scattered over a wide area with highly variable annual accident rates, the use of traffic calmingenables an area-wide approach to be adopted to address such isolated incidents.”It shows, the objective of introducing traffic calming is with broader view of road safety. However the concept of traffic calming is invite motorists to decrease driving speed and pay increase attention to the driving task in order to improve the safety of pedestrians and bicyclists.

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In order to having need for controlling speed in road use for public transportation, London, UK introduce following key notes and types of traffic calming measures.

“1 Horizontal deflections are generally acceptable, except on routes where articulated buses operate.

2 Speed cushions are the preferred vertical measure on bus routesand are acceptable in small numbers when used as part of a combination of traffic calming measures.

3 Speed tables and raised junctions are acceptable in small numbers at key locations, preferably as part of a series of traffic calming measures.

4 Care should be taken to site parking at a sufficient distance from traffic calming measures to avoid hindering bus operation.

5 Round-top road humps are not acceptable on bus routes in London.

6 Trials are currently underway to assess the impact of Vehicle Activated Signs on traffic speeds along bus routes.

7 The cumulative effect of all traffic calming measures must be taken into account regarding increased discomfort to drivers and passengers.

8 The measures used should be suitable for the types of buses that use the route.

9 Appendix A provides a summary of the acceptability of traffic calming measures on bus routes.”

Source: Traffic Calming Measures for Bus Routes(by Bus Priority Team Technical Advice Note-BP2/05, September 2005), UK

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These document further discuses, about the techniques of traffic calming devices such as,

1. Visual appearance – alerting driver’s behavior and encourageto slow down

2. Speed cameras and variable sign boards – measure the averagespeed and identify the speed exceeding vehicles

3. Access control measures – to restrict the access to residential areas

4. Priority changes – giving priority to buses avoid in queue and also reduce junctions’ capacity

5. Horizontal deflection devices – eg. Chicanes, Large Central Island, curb extensions and Chokers

6. Vertical deflection devices – eg. Speed humps, Speed bumps, Speed cushions and Speed tables (to be avoid in bus routes according to UK practice)

METHODOLOGY

In identifying traffic calming practices for road in Sri Lanka, Ifollowed these steps.

1. Getting details from relevant institutions – Road Development Authority

2. Study the manuals published by RDA3. Discuss with responsible officers4. Find details from Google maps5. Visits the locations6. Discuss with neighbourhood about the potentials of measures7. Observe the traffic movement near selected crucial points8. Analyses the situation and get conclusion

Legal Aspects of making regulations for the provisions of TrafficControl Devices lies with the Honorable Minister of Transport in accordance to Section 237 of the Motor Traffic Act (chapter 203)as amended by the Act No. 21 of 1981. No regulation made by Minister under this Act will have legal effect until it has been

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approved by the Parliament and notification of such approval is published in the Gazette.There are no. of authorities having jurisdiction and entrusted with the responsibilities of providing Traffic Act (chapter 203) as amended by Act no. 21 of 1981. 164 the According to the Section following Authorities have the jurisdiction to provide Traffic Control Devices.1) Police Officer not below the rank of the Assistant

Superintendent of Police, for the purpose of any temporary regulation of traffic

2) Local Authority of any area in the case of a roads coming within the purview of that Authority

3) Road Development Authority in the case of road coming withinthe purview of that Authority

4) Sri Lanka Central Transport Board or a Regional Transport Board in concurrence with the Road Development Authority and the Police for the purpose of indicating,a) Place set apart for the parking of omnibuses belonging to

such Boardb) Stopping places for omnibuses belonging to any such Board

Source: Manual on Traffic Control Devices, by Road Development Authority under Ministry of Transport and Highways, Sri Lanka

According to the general practice in Sri Lanka, it can identify following techniques are use,

Visual appearance Speed cameras and variable sign boards Access control measures Priority changes Horizontal deflection devices Vertical deflection devices

Visual AppearanceThese technique is used when approaching junction with high traffic volume or introducing vertical deflected center median with two way flow. This includes arrow point or reflectorized

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crystal plate to maximizing drivers’ attention and visibility in day time as well as night.

Speed cameras and variable sign boardsVery recently it was introduced CCTV camera systems for Colombo city limit in order to detect high speed movements as well as ignorance of all kind of road regulations by motorists. This system has a Central Monitoring Unit control by Sri Lanka Police Department. Further speed detecting techniques uses by Police Department also can be categorized under this section.

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Access control measures and Priority changesThis means a kind of restrictions enforce as a traffic controlling measure. These restrictions should inform to

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motorists within a reasonable distance for purpose of react accordingly. The varies types of sign boards are used to transperthese informations. For that purpose it has introduced standards by RDA through Manual on Traffic Control Device. This informationtransfer system is called “Road signs’’ There are four types of road signs according to the RDA classification.

Prohibitory signs Restrictive signs Mandatory signs Priority signs

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Source: Manual on Traffic Control Devices, by Road Development Authority under Ministry of Transport and Highways, Sri Lanka

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Source: Manual on Traffic Control Devices, by Road Development Authority under Ministry of Transport and Highways, Sri Lanka

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Source: Manual on Traffic Control Devices, by Road Development Authority under Ministry of Transport and Highways, Sri Lanka

Horizontal deflection devices and Vertical deflection devicesFurther to discussed traffic calming measures it can identified some engineering measures use in regulating traffic. Here by having difference in road surface or texture, motorists tend to reduce or control the existing speed. There are several engineering elements comes under these two categories such as Chicanes, Large Central Island, curb extensions, Chokers . Speed humps, Speed bumps, Speed cushions and Speed tables.

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Curb extension Central island

Speed table Speed hump

Among those most widely feel for motorists are speed humps and speed tables. According to RDA point of view they restrict to introduce above traffic calming devices for newly carpeted road as much as possible. But for the secondary roads and due to any special reasons they introduce speed table associate with crossway.

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Speed table associate with crossway near University of Moratuwa

For primary roads with good road texture, RDA has introduced traffic calming device called rumble strips. This is a kind of thermoplastic ink mixed with glass beads to improve the visibility for night time motorists. The strip size is 100 mm width and 5 mm thick and applies to the whole width of the road, when not existing center median or center line mark and other wise apply for half of the road width.The first rumble strips are introduced to Sri Lanka in 2002 for the Galaha road in front of University of Peradeniya. After that,depending on special requirements such as security issues or highrate of recorded road accidents, this device introduce even for the primary roads.

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Arial view of Galaha road near Akbar hall, University of Peradeniya.

Rumble strips of High Level road near Panagoda Army camp example for security reason application.

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Rumble stipr for Bope-Kotte road due high rate of reported accidents and traffic slow down requirement due Katunayaka- Matara Express way construction.

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Close view of rumble strips in Bope-Kotte road, near Army camp

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Children crossing the Bope-Kotte road by crossway associate with rumble strips

CASE STUDY

I studied two cases, one is from the point of victim due to speedhump and the other is from the view of neighborhood near to newlydeveloped main road.

In the first case, he is a production worker of Lanka Walltiles Ltd., Meepe factory and travels daily from his home to factory bymotorcycle. That particular road is arterial road connecting HighLevel road and Colombo-Ingiriya road. And there are two speed humps by the sides of bridge for ela. One day when he passing over the hump as usual he felt kind of negligible pain in his back. After coming home, get his dinner and when to sleep. But after 2-3 hours he felt severe pain in his spinal code. Due to this reason he has admitted to Homagama Base Hospital. According to the doctor diagnosis there is slight displacement in the spinal cord and advised him to be on bed rest for two months. Andhe happened to bear the pain and other difficulties without having job by himself.

Second case is feeling of neighborhood near Bope-Kotte road whereGoogle map shows and experience 3-4 no of death due to road accidents take place after carpeting the road by RDA.(refer the voice cut attached) After complaining and protesting now it has introduced the set of rumble strips at the bend and near the roaddiversion due to Katunayaka-Matara Express Way construction. But the neighborhood point of view it is not sufficient to reduce thespeed of vehicles passing through. I observed some of motorcyclist riding by extreme end of strips to avoid vibration due to strips. Most of the trucks with large tire size does not have any impact by this rumble strips.

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CONCLUSION

It has observed that the speed table to facilitate crossway is has some amount of magnitude towards the calming flow of traffic.But the same time this device cannot introduce primary roads withmore traffic volume. ( as UDA point of view) Same time the rumble strips as traffic calming device for primary road is not supporting much for the objective. And there should be a alternative for improving the safety of pedestrians and non-motorists. And same time it should fulfill the basics of a travelroad. Motorists who use the road should have a reasonable trip time with the trip length.

With considering all above, it shows there should be a proper mechanism to educate the road users both motorists and non-motorists to adjust the present road conditions and the average traffic speed. It is a need to prepare future generation, to copewith the new trends and adapt with new road technology and improvements. And the same time responsible authorities should berethink about viable traffic calming solution for the betterment of both motorist road users as well as neighborhood civilians.

ACKNOWLEDGEMENT

I greatly appreciate the cooperation of yours in preparing this document.

Mr. M. D. Senadeera

Senior Technical Officer,

Road Development Authority, Colombo

Mr. Samantha Paranaliyanage

Godagama, Homagama.

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And the public community that gives true evidence for my study,

Thank you….!

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