SHAH ALAM – The Klang Valley has an expanding highway network, but traffic congestion remains a worsening daily reality, particularly during the morning and evening peak hours.
Despite having about 20 major toll highways in operation, including the New Klang Valley Expressway, Damansara–Puchong Expressway, Shah Alam Expressway, Duta–Ulu Klang Expressway and Sungai Besi–Ulu Klang Elevated Expressway, traffic flow has yet to improve.
Universiti Kebangsaan Malaysia Department of Civil Engineering senior lecturer Associate Professor Ir Dr Nur Izzi Md Yusoff said the situation showed that congestion in the Klang Valley was not caused by a lack of highways, but by a failure in managing the overall urban traffic network system.
He said the addition of new highways only increased vehicle inflow into already congested interchanges, exit ramps and urban roads.
"When road capacity is increased, more users choose to drive because the journey appears easier. This phenomenon is known as induced demand, where the increase in vehicles eventually fills up the available space," he told Sinar.
He said the problem was worsened by heavy dependence on private vehicles and land-use planning that did not align with road infrastructure development.
Izzi said congestion in the Klang Valley was often triggered when fast-moving highway traffic was funnelled into narrow bottlenecks such as short exit ramps, limited flyovers and signal-controlled urban roads.
"Weaving conditions, where vehicles merge and exit over short distances, also disrupt traffic flow and create braking waves or shockwaves even without accidents," he said.
"During peak hours, minor disruptions at connection points can lock entire corridors, making highways appear full even though the root problem starts at the network edges," he added.
He said the spill-over effect also occurred when congestion on one highway spread to others through alternative routes, causing previously smooth roads to become congested.
He said recurring congestion despite road widening or upgrades was not due to construction failure, but a failure of approach.
New roads often attracted fresh development and generated more trips, merely shifting the problem elsewhere without resolving it holistically.
In daily life, this system failure translated into significant time and cost losses, with urban workers spending more than two hours a day commuting and experiencing mental and physical fatigue before starting work.
Other studies showed urban workers could lose hundreds of hours each year due to congestion, with productivity losses amounting to tens of billions of ringgit to the national economy.
Izzi stressed that smart traffic technologies, including AI-based systems and navigation tools, functioned only as management aids rather than absolute solutions.
"If demand exceeds physical capacity, technology can only redistribute congestion, not eliminate it," he said.
He warned that without coordination between toll highways, federal roads and urban streets, the urban traffic system would remain highly vulnerable, especially during peak periods or minor disruptions.
In the long term, Izzi said the Klang Valley risked reaching a state where the traffic network lost its ability to recover flow, turning congestion into a persistent daily condition.
He said solutions should go beyond adding lanes on main routes and instead focus on exit ramp design, traffic distribution and system-wide coordination.
"Adding highways without changing the approach will only keep shifting the problem. If it is not addressed comprehensively, congestion risks becoming permanent," he said.