The choice of road materials worldwide is a layered process, influenced by factors such as community engagement, local preferences, and safety considerations, often constrained by budgetary concerns and occasionally entangled in procurement-related corruption risks. Asphalt favours higher speeds, while paver blocks may slow traffic for safety.

Factors such as climate, traffic, durability and maintenance costs influence material choice. In some cases, politics, lobbying, or vested interests may also influence these decisions, highlighting the need for transparent and accountable decision-making processes. Striking a balance between these factors is essential for effective and sustainable road infrastructure development.

Mumbai has a long history of controversy around the use of paver blocks, and more recently, the controversy has sprung up in Karachi following the use of paver blocks in the construction of the Gulistan-i-Jauhar Underpass in August 2023.

Furthermore, on Sept 8, 2023, the KMC proceeded with the placement of paver blocks at Shahrah-i-Quaideen near Khudadad Colony, continuing this controversial practice in the city.

A means of corruption in Karachi?

The use of paver blocks for road construction in Karachi has been met with scepticism and allegations of corruption against the Sindh government and Karachi Metropolitan Corporation (KMC), especially on social media.

Specifically, the construction of the Gulistan-i-Jauhar underpass with a road surface of paver blocks has drawn criticism from residents. They argue that the blocks have not been properly levelled or cemented, resulting in gaps which create an uncomfortable ride for commuters.

Residents are avoiding the underpass, which is supposed to be a faster, signal-free corridor, and opting for longer routes instead. In essence, the millions, if not billions of rupees spent on the underpass are being under-utilised at best and wasted at worst. Instead of making the commute more smooth, it is causing a major inconvenience for the public.

The perceived lack of attention to quality in the construction process has led to accusations that the contractors prioritised personal financial gain over the welfare of the public.

The citizens of Karachi are curious about the political motivations behind this choice — who benefits from it, who provides an engineering perspective on such projects, and lastly, who grants them approval.

The lack of transparency and response from the KMC and the mayor of Karachi — Murtaza Wahab — has fuelled these concerns and led to accusations of incompetence and hidden agendas.

From Mumbai to Karachi

Paver blocks were first introduced in Mumbai in 2002. At the time they were met with optimism, but they lost popularity as they became loose and formed potholes over time. Recognising the need for improvement, the Brihanmumbai Municipal Corporation (BMC) made a pivotal decision in 2011 to reduce the use of paver blocks in favour of more durable materials such as asphalt or concrete.

Subsequently, in 2015, the BMC embarked on a project to remove paver blocks and replace them with asphalt for road construction. This significant shift signalled a conscious effort to address the concerns raised by residents regarding broken paver blocks and the subsequent accidents and injuries they caused.

However, despite these efforts in some places, the paver block controversy persisted, and the municipal corporation continued using the blocks for road construction in other areas. This also led to legal action from concerned citizens.

On searching the keywords ‘paver blocks controversy in Mumbai’ on Google, a number of results show up such as the following headlines: “Flop in Mumbai: Paver blocks sanctioned for rural areas. Why?”, “Freak mishap reignites debate on paver blocks in Mumbai” and “Mumbai Standing Committee rejected BMC’s proposal to utilise paver blocks on roads”.

Despite research that demonstrates the unsuitability of paver blocks for road construction, their prevalence in Mumbai persists. Not only have citizens voiced their concerns, but recurring potholes — particularly during the monsoon season — have required high maintenance and repair for these roads, making the blocks a financial drain with minimal return. This has led many to question the BMC’s commitment to effectively address the condition of Mumbai’s roads.

Paver blocks vs asphalt

Although paver blocks may incur a higher initial expense, they come with many advantages such as simple maintenance, visual aesthetics and access to utility lines. They allow for creative designs and patterns, making roads visually attractive, especially in urban and historical areas. Using paver blocks to beautify footpaths and improve pedestrian infrastructure is a common practice in cities around the world. These blocks are also found in residential streets and lanes, especially streets that have low and slow-moving vehicular traffic.

The blocks can be easily removed and replaced, granting easy access to underground utilities such as water, gas, and electricity lines without necessitating extensive excavation, reducing disruption and maintenance costs.

Another benefit is their potential for water permeability. Some paver block designs allow water to pass through, which can reduce surface runoff and the risk of flooding. However, it is important to note that proper installation and maintenance are crucial to ensure the effectiveness of permeable paver systems and to prevent damage.

For road repairs involving patches or potholes, paver blocks are a favourable option. They can be used for temporary roads that are only needed for a short period, such as for camps or festivals. Once the purpose is served, the paver blocks can be easily removed and reused elsewhere.

The blocks are easier to install and remove as compared to asphalt and concrete roads. This makes them particularly suitable for areas that require frequent repairs or maintenance of underground utility lines. Paver blocks are also known for their ability to withstand high friction, making them suitable for traffic junctions and roundabouts where heavy-duty vehicles frequently operate.

Using paver blocks as the primary construction material is warranted in geographical areas where these factors align with the long-term objectives of the community. Nevertheless, such expenditures must be subject to a meticulous evaluation on a case-by-case basis, taking into account the unique demands and fiscal limitations of the community in question.

In the ‘developed’ world, asphalt is commonly preferred, owing to its commendable durability, minimal maintenance requirements and cost-effectiveness in high-traffic areas. The use of paver blocks is sometimes restricted due to existing infrastructural limitations and the need for significant investments and adaptations.

It is when these blocks are used to build or repair roads with high traffic density that challenges arise. In the most severe instances, loose blocks pose a hazard to motorcyclists, potentially leading to accidents. Even cars are not immune to the consequences of uneven blocks which can cause damage to the vehicle’s underbody, tire rims, or alloys. The decision to use paver blocks on busy roads appears to prioritise the financial interests of contractors at the expense of motorist safety.

Paver blocks not for high-speed roads

Paver blocks are not suitable for high-speed roads due to their uneven surface, which can compromise vehicle stability and traction, especially in adverse weather conditions. This can lead to a higher risk of accidents and reduced control over vehicles. To address these safety concerns, it is crucial to implement proper design, and maintenance, and consider road conditions when utilising paver blocks on high-speed roads.

One of the major drawbacks of paver blocks is their lack of grip when wet. This poses a significant risk of skidding and slipping, particularly for smaller vehicles. Using textured or permeable pavers that improve traction is advised to address this problem. Additionally, the noise generated by vehicles on paver block surfaces can be excessively loud, particularly when travelling at speeds above 50 km/h. This can be both a nuisance and a safety concern.

In some cities, paver blocks are used in short stretches of five-20 meters where frequent road repairs are required due to underground water pipes bursting. This limited usage helps mitigate some of the issues associated with paver blocks while addressing the specific needs of the infrastructure.

Having a people-centred approach should be at the core of all urban planning, including the construction of roads. Authorities need to take corrective measures when citizens bring their concerns and problems forward and should provide a clear rationale to ensure public trust and transparency in the decision-making process.

The header image shows an asphalt road with underlines of paver blocks.