Decoding Bengaluru's white-topping vs asphalt debate

Recently, the high court asked the BBMP to explain the rationale behind whitetopped roads. What are the concerns about these expensive roads?

While hearing the issues related to road repairs and drainage management in Bengaluru last week, the Karnataka High Court asked Bruhat Bengaluru Mahanagara Palike (BBMP) to respond to concerns about the science behind the white topping of roads. The court’s concern was that the city’s streets must be evaluated from a broader environmental and structural perspective rather than focusing solely on aesthetics or short-term durability. 

The court asked whether BBMP maintained the roads regularly or only during monsoons. The bench asked how the method differs from other road surfacing techniques and how it is the most appropriate solution for water seepage and other issues.

The BBMP counsel defended the white topping technique as a solution to improve road conditions in Bengaluru but could not provide a detailed justification. The BBMP has been asked to submit detailed justification for white-topping by the next hearing, slated for February 20. 

This raises questions about a sustainable approach to urban planning and road maintenance in Bengaluru.

Problems and concerns

While citizens demand pothole-free roads, the measures the BBMP is taking to prevent potholes are not pleasing everyone. 

Trees falling due to the lack of underground water seepage due to increased concretisation is a big concern in Bengaluru. Many activists say concretised roads only add to the problem. 

For example, people near M N Krishna Rao Park, Basavanagudi, believe that concretising roads in the area led to the falling of six huge trees in the area. They believe concretised roads starve the roots of trees as no water seeps into the ground during rains.

A citizen activist who preferred anonymity said finishing white-topped roads needs to be rough. Otherwise, it will lead to skidding and sliding of two-wheelers, leading to accidents. 

“When 70% of the vehicles are two-wheelers, the design should include them to ensure road safety,” he added. He explained that water-absorbent cement can be used in white-topping, which prevents water from staying on the road.

The cost of white-topping in Bengaluru has escalated over the years. Initially, it was around Rs 9-10 crore per kilometre, but it was raised to Rs 12-16 crore per kilometre.

The high initial cost has been a cause for concern among activists. “It does not make sense to say the road will last 25 years and spend Rs 18 crore per kilometre. Regular asphalted roads should last at least five years; the BBMP should have road maintenance embedded into tenders and hold the contractors accountable when potholes appear. Failure to do this often results in pothole filling and road relaying expenditures. If you fix this, this is enough to maintain the roads in good condition,” says an activist. He cites flooding on Cunningham Road as an example of the failure of white topping to provide for proper drainage.

The BBMP officials say they have a clear cost-benefit analysis of asphalt roads versus white-topped roads. However, they did not share it with DH.

Increased road height is another concern people highlight. “Adding a concrete layer raises the road level, which can cause water to seep into adjacent properties and affect existing infrastructure,” says Raghavendra M, a resident of Rajajinagar.

BBMP explains

BBMP officials highlight enhanced durability, improved surface quality, and reduced maintenance costs in favour of white-topped roads. 

Lokesh Mahadevaiah, chief engineer of BBMP who is in charge of white-topping, says the impression among environmentalists that asphalted roads will absorb water is wrong. “If asphalted roads absorb water, the road will be damaged. Water is the biggest enemy of asphalt. Bengaluru has a good amount of green cover. Water drops keep falling long after rains are over on many roads. This causes waterlogs on roads during the rainy season and contributes to potholes,” he explains. 

He gives the example of Nrupatunga Road. “The road was always waterlogged, and potholes were formed often. In 2016, we white-topped the road. There have been no potholes, and we have not spent a single penny on this road in eight years,” he adds.

He argues that the environmental impact angle put forward by citizens is not entirely logical. “Asphalt needs bitumen, a petroleum product - a natural resource, which has its own environmental impact along with reduced road life. It is not economical enough,” he adds.

What about the cost? “If we are just concretising, the cost is double the price of asphalting. However, we include shifting utilities such as optical fibre cables, water, gas, and electrical lines to separate ducts. We also add ducts across the road. This helps avoid road cutting, as anyone needing the connections has to take them through these ducts. Like in TenderSURE roads, future road-cutting is not allowed in white-topped roads. This helps maintain the road for a long time,” he explains. This reduces maintenance costs and becomes economical when the 25-year timeline is considered.

“Karnataka Power Transmission Corporation Limited power lines and trunk lines of BWSSB are the only exceptions to utilities that cannot be shifted,” he says. A white-topped road must be broken only when some major repair is needed for these lines. Otherwise, no permission will be given to mess with the road,” he says.

“We dig percolation pits in the drains beside the newer roads to be white-topped to help underground water recharge. We are not touching the existing concrete drains because it amounts to wasteful expenditure. Still, wherever the drains are getting re-done, we are making sure to include provision for rainwater seepage,” he adds. 

White-topping is not the only way to increase the durability of a road, says Lokesh. “We used the stone-metric asphalting method (where more durable aggregates, higher asphalt content and, typically, a modified asphalt binder and fibres are mixed) on Kempegowda Road in 2016. “Even after nine years, the road is in excellent condition,” he explains.

This was a pilot project. Another stretch from Cauvery Bhavan to the Majestic area was done using the same method. The method was also used in an area on Modi Hospital Road, which was always waterlogged. 

However, this technique is not widely used in BBMP’s road works. Sources say this is because it costs a little more than regular asphalting.

While white-topping offers benefits like enhanced durability and reduced maintenance, it also presents challenges such as high initial costs and potential environmental impacts. Careful planning and execution are essential to maximise the advantages and mitigate the drawbacks of this approach, say experts.

Quality under scanner

Meanwhile, N R Ramesh, ex-BBMP councillor, filed a Lokayulta complaint against road works in Bengaluru in November 2024, saying that contractors bribed heavily to secure contracts. In the same complaint, he alleged that contractors were using M-20 grade cement concrete mix instead of M-40 grade cement concrete mix mandated in tenders, making the roads turn white instead of grey. This also results in lower quality of white-topping, he added in the complaint against the poor quality of road works with 4,113 pages of material. The case is ongoing.

Two phases of white-topping works are already underway. The Karnataka government recently decided to drop 92 roads from the third phase of the white-topping project, citing various reasons. The total cost was estimated at Rs 1,172 crore.