CHENNAI: The recent Cuddalore accident, which claimed nine lives, has brought renewed attention to the design of low-level centre medians on national highways. While a section of road safety experts and the police have called for the installation of barriers on both sides of the median and increase its height to reduce crash impact and prevent vehicles from crossing into the opposite carriageway, the National Highways Authority of India (NHAI) has maintained that there was no flaw in the road geometry or median design at the accident site.
The NHAI said the 20 cm-high low-level median complies with prescribed safety standards and argued that increasing the height of the median could potentially result in more fatalities during highway accidents.
On December 24, an SETC bus en route to Chennai, carrying around 30 people, allegedly lost control, crossed the centre median at Ezhuthur on the Tiruchy-Chennai NH, and entered the opposite carriageway, where it collided with two cars. The height of the centre median on the NH is only 200 mm and about two metres wide.
According to the Indian Roads Congress (IRC) — the apex technical authority that sets highway design standards — the amended Rule 73 (2023) recommends a minimum desirable width of 5 m for low-level medians. In contrast, the low-level median on the Chennai bypass, the Tindivanam-Kanniyakumari NH, and several other locations across the state is only two metres wide.
Dr Bhargav Maitra, Professor and Principal Co-ordinator of Road Safety & Traffic Engineering, IIT Kharagpur, who is also member of multiple technical committees of IRC told TNIE that NHAI should consider installing barriers on depressed central medians on highways to absorb kinetic energy and reduce vehicle speeds. He noted that IRC Rule 73 permits low-level medians, however, safety standards and norms should not be treated as sacrosanct, akin to religious doctrines.
“IRC norms are not updated in line with changes in vehicle design, speed, and driver behaviour every five years. The vehicles plying on roads today are vastly different from those designed a decade ago. Even if a median complies with existing norms, we should not hesitate to revisit designs in light of changing conditions,” he said, and pointed out that the distance between upstream and downstream vehicles travelling at 100 kmph should not be as little as two metres.
Echoing similar views, Ravishankar Rajaraman, road safety expert at CUMTA, said that as per IRC 119:2015 norms, if the average daily traffic exceeds 20,000 passenger car units, the width of a low-level median should be between 9 and 11 m. “Currently, India lacks testing agencies to evaluate and certify median barriers for impacts involving heavy vehicles. Medians require barriers to prevent vehicles from crossing over,” he said.
Cuddalore SP S Jeyakumar told TNIE that there have been multiple incidents of vehicles crossing over into the opposite carriageway, resulting in heavy fatalities, particularly involving SUVs and buses. “When a vehicle enters the opposite carriageway, motorists travelling in the correct direction have very little time to react, often leading to fatal accidents. During district road safety meetings, the collector and I have repeatedly urged NHAI to increase the height of the median, but the requests have not been implemented,” he said.
Arun Prasad, project director, NHAI (Tiruchy), said there was no engineering or design flaw in the highway at the accident site. “The road was constructed in 2009, and a two-metre-wide median was provided in accordance with the IRC norms prevailing at the time. With regard to installing barriers, a decision will be taken if a formal request is received from stakeholders,” he said.
However, a senior NHAI official explained that low-level medians are safer. “When the wheels of a speeding vehicle come into contact with a low-height median, the vehicle is usually deflected back onto the carriageway without major disruption. Increasing the median height could potentially lead to more severe accidents. Several studies on this issue have been conducted by NHAI and other agencies, which conclude that low-level medians are the safest,” the official said.