Traffic diversions are essential to ensure the safety and efficiency of traffic flow in and around work zones during road construction. These diversions are put in place to protect both the workers and equipment involved in the construction process. Furthermore, they allow for the uninterrupted movement of motor vehicles, bicycles, and pedestrians, as well as transit operations and access to properties and utilities. By carefully planning and implementing traffic diversions, road construction projects can be carried out with minimal disruption to the overall traffic flow, ensuring the safety of all road users while maintaining access to important destinations.
Traffic diversion signs
There are two main types of traffic diversion.
1. Passage of Traffic on the Existing Carriageway under Improvement
When a section of an existing roadway is being used for traffic passage while construction is ongoing, it is necessary to provide treated shoulders on the side where work is not being carried out. These shoulders must be at least 1.5 meters wide and treated with a minimum 150 mm thick granular base course overlaid with a bituminous surface dressing. It is also important to maintain the surface of the treated shoulder while it is being used by traffic.
To limit the disruption caused by road works, the continuous length of road works that can be carried out in one place is limited to 500 meters. However, if longer stretches of road work are allowed, provision must be made for overtaking by providing an additional paved width of 2.5 meters at every 0.5 kilometer interval.
In cases where an existing two-lane road is being widened to four lanes, it is necessary to first construct the additional two lanes. Once the additional lanes are constructed, traffic is diverted to them and work can then be carried out on the existing carriageway treatment. After the work on the existing carriageway treatment is completed, the treated shoulder that was constructed for traffic diversion should be dismantled, the debris disposed of, and the area cleared.
2. Passage of Traffic along with a Temporary Diversion
To enable traffic flow in areas where it is not possible to use a section of the road, a temporary diversion will be constructed. The temporary diversion will consist of a 7-meter carriageway and 2.5-meter earthen shoulders on both sides, resulting in a total width of 12 meters for the roadway. The 7-meter width will be divided into three layers, starting with a 200 mm granular sub base that will be compacted, followed by a 225 mm granular base course that will also be compacted. The topmost layer will be a premix carpet with seal coat/mix seal surfacing.
The alignment and longitudinal section of the diversion will be designed to facilitate smooth traffic flow. The junctions and temporary cross drainage provision will also be incorporated into the design to ensure safe passage of vehicles. Overall, the temporary diversion will provide a safe and efficient alternative route for traffic, allowing work to be carried out on the affected section of the road.
Traffic Safety and Control
Before starting any construction work on a highway, it is necessary to plan and agree upon a phased program for the diversion of traffic. This is to ensure that the flow of traffic is not disrupted and that drivers are aware of any changes to the usual route.
During road construction, it is important to take all necessary measures to ensure the safety of the traffic passing through or approaching the section of the highway under improvement. This can be achieved by providing and erecting barricades that are strong enough to resist violation. These barricades should be painted with alternate black and white stripes and erected on either side of the carriageway that is closed to traffic. Additionally, flags, lights, signs, markings, and flagmen should be used to protect and inform drivers.
At night, red lanterns or warning lights should be mounted on the barricades and kept lit throughout from sunset to sunrise. The places where traffic is required to deviate from its normal path should be clearly marked with painted drums or pavement markings. At night, lanterns or other suitable light sources should be used to illuminate the passage.
When traffic needs to pass through a section of the highway that is insufficient for two-lane traffic, a one-way traffic operation must be formed. This can be accomplished with the help of temporary traffic signals or flagmen stationed on opposite sides at all times. The flagmen should be equipped with green and red flags and lanterns or lights for traffic regulation.
On both sides of the highway, suitable regulatory and warning signs should be installed to guide road users. At least two signs should be installed on each approach, one close to the point where the transition of the carriageway begins and the other 120 meters away.
Maintenance of Diversions and Traffic Control Devices
The proper maintenance of traffic control devices and the riding surface of diversions is essential until they are used for traffic. These devices include signs, barriers, lights, and other traffic control mechanisms. It is important that they are kept in a satisfactory condition to ensure the safety of drivers and pedestrians.
Moreover, the temporary path or diversion must be kept free of dust, which can be achieved by spraying water on the surface frequently. This is important to prevent dust from affecting the visibility of drivers and pedestrians, which can lead to accidents. Therefore, it is imperative to ensure that the temporary path is regularly maintained and cleaned to provide a safe environment for those using it.
In conclusion, the maintenance of traffic control devices and the temporary path or diversion is crucial to ensure the safety of drivers and pedestrians. Regular maintenance of these devices and the cleaning of the riding surface by spraying water frequently can prevent accidents caused by dust and other factors. Therefore, it is important to prioritize the maintenance of these elements to provide a safe environment for all those using the road.
FAQs
Why is the need for providing traffic diversion during road construction?
Traffic diversions serve the dual purpose of ensuring the safety and efficiency of traffic movement during road construction, while also safeguarding the workers and equipment deployed for this purpose. They are designed to facilitate the smooth flow of motor vehicles, bicycles, and pedestrian traffic, as well as ensuring uninterrupted access to properties and utilities.
By redirecting traffic through or around the work zone, these diversions aim to maintain the continuity of transportation services and transit operations. They are an essential component of road construction projects, as they help to minimize disruption and inconvenience to the public while enabling construction work to proceed without interruption.
Overall, traffic diversions play a crucial role in ensuring the safety and efficiency of transportation during road construction, while also balancing the needs of various stakeholders, including the workers, motorists, cyclists, pedestrians, and transit operators. They are an essential tool in the hands of road construction authorities, enabling them to manage traffic flow and minimize disruptions, while also ensuring the safety of all road users.
What are the safety measures undertaken for the safety of traffic during road construction?
When road construction is taking place, it is essential to prioritize the safety of traffic. This can be achieved through various measures, such as erecting barricades, placing flags and lights, putting up signs and markings, and stationing flagmen. These measures serve to protect and inform drivers who are passing through or approaching the section of the highway that is being improved.
Barricades are a crucial element in ensuring safety during road construction. They act as a physical barrier to prevent vehicles from entering the work zone and endangering the workers or themselves. Additionally, flags and lights are highly visible indicators that signal drivers of the ongoing construction work, even from a distance. This is important to ensure that drivers are prepared to slow down and navigate the work zone safely.
Signs and markings play a vital role in providing information to drivers about the construction work ahead. They can indicate the appropriate speed limit, the presence of detours, and the location of the construction site. This helps drivers to navigate the area with caution and avoid potential hazards.
Finally, flagmen are stationed in the work zone to provide real-time information and guidance to drivers. They can help direct traffic, provide information on the status of the work, and signal drivers to slow down or stop as necessary. This human presence helps to ensure that drivers remain alert and responsive to changing conditions on the road.
In summary, it is critical to undertake all necessary measures to ensure the safety of traffic during road construction. This can be achieved through the use of barricades, flags, lights, signs, markings, and flagmen. These measures serve to protect and inform drivers who are passing through or approaching the section of the highway that is under improvement. By implementing these measures, we can reduce the risk of accidents and ensure that road construction work can be completed safely and efficiently.
What are the treatments carried out on road shoulders of the traffic diversions?
To ensure proper treatment of the shoulder, it is necessary to have a granular base course that is at least 150 mm thick. This base course should be overlaid with a bituminous surface dressing that is at least 1.5 m wide. It is essential to maintain the surface of the shoulder during the time it is being used by traffic to ensure its longevity and effectiveness. Proper maintenance and adherence to these specifications are crucial to ensure the durability and functionality of the shoulder.