Dhaka–Chattogram Highway Was Outgrown Before It Fully Opened
The Dhaka–Chattogram Highway is often called Bangladesh's economic lifeline. It connects the capital with Chattogram Port, which handles around 92% of the country's seaborne import-export trade and almost 98% of containerised cargo. In 2025 alone, the port handled a record 3.41 million TEUs and about 138 million tonnes of cargo.
Yet the road carrying most of that economic activity has a basic problem: Bangladesh spent thousands of crores widening it to four lanes, but traffic demand was already approaching—or exceeding—the practical capacity of the corridor before the project was fully opened. That makes the Dhaka–Chattogram Highway less a story of an old road becoming congested and more a story of infrastructure that was almost too small from the beginning.
The Four-Lane Highway Was Already Late
The 190-kilometre Daudkandi–Chattogram section was formally opened as a four-lane highway in July 2016. The project ultimately cost roughly Tk 3,400–3,800 crore, depending on whether later completion costs or the inauguration-stage figure is used. But the warning signs existed years earlier.
A JICA study estimated that a four-lane section of N1 could handle around 60,000 passenger car units (PCU) per day. Traffic surveys conducted in 2012 found approximately:
78,000 PCU/day at Kanchpur
73,300 PCU/day at Meghna and Gumti
Around 60,000 PCU/day as the estimated four-lane capacity
In other words, some of the highway's most important bottlenecks were already carrying traffic above the estimated capacity of a four-lane road four years before the widening project officially opened. ADB reached a similar conclusion when studying a separate Dhaka–Chattogram expressway. Based on 2009 traffic, it projected that even the new four-lane highway would become saturated shortly after 2020 because of mixed traffic, intersections, roadside settlements and rapidly rising vehicle numbers.
The Road Was Also Underdesigned for Heavy Loads
Vehicle numbers were not the only problem. The highway was carrying much heavier freight loads than its pavement assumptions anticipated.
Roads and Highways Department later said the upgraded road had been designed for about 98 million equivalent standard axle loads (ESAL) over a 10-year design life. A 2015 survey, however, found projected loading of roughly 305 million ESAL—more than three times the design assumption.
That helps explain why maintenance problems appeared so quickly after construction. A road dominated by container trucks and heavy freight deteriorates very differently from one carrying mainly passenger vehicles.
The problem was therefore built into the corridor's economics. Chattogram Port kept growing, industry expanded around Dhaka and Chattogram and the highway remained the easiest way to move most high-value cargo.
Chattogram Port Keeps Adding More Traffic
The pressure has not stopped. Chattogram Port handled about 3.52 million TEUs in FY2025–26, up 6.76% from the previous fiscal year. Cargo throughput also reached a record 137.74 million tonnes.
Current planning documents say roughly 30,000 vehicles use the highway every day, with trucks making up around 30–40% of traffic. The corridor also carries around 96% of cargo moving to and from Chattogram Port by road, according to the government's latest expressway proposal.
This means growth at the port immediately becomes pressure on N1 unless rail and inland waterways absorb a much larger share. That modal shift has not happened fast enough.
Four Lanes Do Not Operate Like Four Expressway Lanes
The bigger problem is that N1 is not a fully access-controlled expressway. Local buses stop along the route, while trucks enter filling stations and factories directly from the highway. Markets, intersections, U-turns, roadside development and slow-moving vehicles also interrupt long-distance traffic.
That matters because lane count alone does not determine road capacity. A four-lane access-controlled expressway can move traffic far more efficiently than a four-lane highway where national freight, intercity buses and local traffic constantly interact.
The consequences remain visible in 2026. In April, congestion across roughly 30 kilometres between Chattogram City Gate and Sitakunda became so severe that journeys normally taking 30 minutes reportedly took nearly three hours. Heavy vehicles queuing at filling stations occupied portions of the highway and effectively reduced available capacity.
Bangladesh Is Now Planning Another Massive Upgrade
A decade after opening the four-lane highway, the government is again looking for a much larger solution. The current proposal is to transform about 233 kilometres of the Dhaka–Chattogram corridor into a six-lane access-controlled expressway with service roads on both sides. The preliminary estimated cost is around Tk 71,850 crore, with the government seeking more than Tk 55,000 crore in foreign loans.
The plan includes flyovers, interchanges, underpasses, service roads and intelligent transport systems. Those features matter as much as adding lanes because they would separate long-distance freight from local roadside traffic.
But the scale of the new proposal also exposes the weakness of the previous planning cycle. Bangladesh spent thousands of crores turning N1 into four lanes, yet less than a decade later it is considering spending tens of thousands of crores more to create the type of controlled corridor that earlier studies had already suggested would eventually be necessary.
The Real Problem Was Not Building Four Lanes
Upgrading the old two-lane highway was necessary. Without it, congestion would have become far worse much earlier.
The planning weakness was assuming that four conventional lanes could serve as the long-term solution for the country's most important economic corridor while trade, container traffic, heavy trucking and roadside development were all increasing rapidly.
The evidence shows how early the problem appeared:
critical sections were already above estimated four-lane PCU capacity in 2012;
pavement loading was measured at more than three times the original design assumption by 2015;
ADB had warned the four-lane highway could become saturated shortly after 2020;
Chattogram Port now handles record cargo and container volumes;
and Bangladesh is already planning a Tk 71,850 crore replacement-level upgrade.
The Dhaka–Chattogram Highway therefore offers a simple infrastructure lesson: a road serving the country's main port cannot be planned only around today's traffic. It has to be designed around the economic activity it is expected to create. Bangladesh widened N1 to solve congestion, but traffic growth was faster than the solution.
The country is now preparing to upgrade the same corridor again because the four-lane highway was never likely to remain enough for very long. The problem was not that Bangladesh expanded the road; it was that the scale of the solution failed to keep pace with the scale of the corridor it was supposed to serve.
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