08 September,2026 07:50 AM IST | Mumbai | Ranjeet Jadhav
The Bandra-Worli Sea Link has largely remained free of the potholes and surface damage seen on several city roads. Pic/Shadab Khan
Mumbai's roads are not all built to fail. The 17-year-old Bandra-Worli Sea Link and newer Coastal Road stretches have largely held up, while potholes, bumps and crumbling surfaces continue to plague several ordinary city roads. So what makes the difference? Experts point to everything from pavement design, materials and compaction to drainage, traffic loads and, crucially, what happens to a road after it is built - including repeated digging for utilities.
The Bandra-Worli Sea Link has largely remained free of the potholes and surface damage seen on several city roads. Pic/Shadab Khan
"Minor defects, including potholes, are attended to through routine maintenance and patchwork. A complete renewal of the surface is generally carried out at intervals of around 5 years, depending on its condition," said an MSRDC engineer.
Resurfacing the Sea Link is also different from resurfacing an ordinary road. Adding a fresh layer over the existing surface would increase the load on the bridge and change the road level. When the surface is completely renewed, the existing layer is removed to a depth of 25 mm and replaced with a new layer of the same thickness.
A pothole near Mehboob Studio in Bandra. Pic/Shadab Khan
"This process allows us to maintain the original road level and, at the same time, prevents any unnecessary additional load from being imposed on the bridge. The maintenance work is therefore carried out keeping both the road condition and the structural safety of the Sea Link in mind," the engineer said.
Girish Jaysing Arekar, council member, Indian Road Congress, said a road constructed according to IRC norms and properly maintained should not develop potholes within a few months. "If a road is constructed as per Indian Roads Congress (IRC) norms and specifications, potholes should not appear for at least three to five years, provided the road is properly maintained. On high-traffic roads, some wear and tear is expected over time, but the surface should gradually wear rather than develop potholes within a few months of construction," he said.
A bumpy stretch near Poisar Metro station in Kandivli. Pic/Satej Shinde
Material: Poor-quality bitumen or aggregates can weaken the road.
Workmanship: Incorrect laying, rolling or compaction can leave weak spots in the pavement.
Drainage: Water can seep into the road's underlying layers and weaken its foundation.
Camber: The road needs the correct slope to allow rainwater to drain away.
Traffic: Heavy vehicles such as trucks and trailers put greater stress on the pavement.
"Bitumen and water do not work well together, and even a good-quality road can develop potholes if water is allowed to remain on or beneath the surface," Arekar said.
It can, particularly when roads regularly carry heavily loaded trucks, trailers and other heavy vehicles.
Repeated heavy loads can cause cracks and other weaknesses in the pavement. Once water enters those cracks, deterioration can accelerate.
But Arekar said there is no single reason why the Sea Link or Coastal Road performs differently from ordinary city roads.
"The quality of materials, construction technique, compaction, pavement design, drainage, camber, traffic load and maintenance all play a role," he said.
5.6 km: Length of the Bandra-Worli Sea Link
65 mm: Original wearing course laid over the concrete bridge deck
40 mm: Bituminous carpet
25 mm: Mastic asphalt
Around 5 years: Typical interval for complete surface renewal, depending on condition
mid-day photographers visited roads under BMC jurisdiction and found potholes and uneven surfaces affecting motorists.
Road visited: Akurli Road, Kandivli
Abhijit Bangar, additional municipal commissioner (Projects), BMC
While constructing or resurfacing asphalt/bitumen roads in Mumbai, does the BMC strictly follow Indian Roads Congress (IRC) guidelines and standards? Is compliance with these guidelines mandatory in BMC tenders? If so, which IRC standards apply?
"Yes, we follow the IRC guidelines, and their compliance is ensured through mandatory conditions of our road tenders. Standard specified requirements listed in our road tenders include technical specifications like required depth, levels/layers across the road's height, specific materials with specific thickness for those layers (materials like GSB, WMM, DLC, PQC), compaction standards, testing standards, specific material quality, concrete mix design (fixed aggregates, water-cement ratio)."
Are there any key differences in the design, materials, construction methodology, drainage and quality-control measures used for asphalt roads on projects such as the Coastal Road compared with conventional BMC roads?
"There are no major differences as such with their overall quality standards in their contracts, design and drainage is of course requirement based - like it's different for say a bridge than a flat road, but a flexible pavement (asphalt based) and rigid pavement (concrete based) have their own set of quality standards and contractors are mandated to follow the same standards for all roads. Notably, the same contractors who have made these âspecial' projects have also constructed regular city roads with the same set of guidelines and applicable materials. Though the quality of these special projects differs, most asphalt roads are subjected to the same level of IRC-compliant quality mandates; the same is the case with concrete roads, although they are more durable."
Why many BMC asphalt roads develop potholes and uneven surfaces, particularly during or after the monsoon, while roads on major projects such as the Coastal Road appear to have comparatively fewer such problems despite also using asphalt/bitumen?
"Although the bitumen quality differs for these major bridges, one of the key differentiating factors for water-based damage for asphalt roads is whether one has utilities under it and has gone through trenching.
"Pavement on projects like BWSL and Coastal Road has fared well because their pavement integrity remains unhampered. While most regular roads have utilities like electricity lines under them and often experience both unauthorised and authorised digging, trenching disrupts the road's integrity and leaves the pavement more susceptible to damage. This is even more so in roads in areas where water does not escape easily.
"New asphalt roads which go through trenching also further lose on repairs at the contractor's cost under the Defect Liability Period, as opposed to the case of Cement Concrete roads - trenching there is precise and doesn't cause larger damage to the road due to rigid concrete, one of the reasons why CC roads are preferred by us.
"Another factor for poor-performing roads that remains is shoddy work from the contractors. They don't exercise the required quality standards they agreed to, resulting in bad roads, for which systematic changes such as harsher penalties are required. We are working on these issues."
