The newly opened $4.3 billion Marina Coastal Expressway (MCE) is a breathtaking engineering feat by any measure. Part of the mega tunnel (five lanes in each direction) under the seabed had to be built in soft marine clay, while rechannelling 2,000 cubic metres of water a second flowing from the Marina Bay.

After four years of complex work costing a prodigious $860 million a kilometre, the sleek expressway deserved a triumphal opening rather than two-hour delays for users resulting from snarls at a few points en route.

First-day teething problems are to be expected, of course, but to what extent can glitches be anticipated when dealing with high volumes and multiple connections? This is a challenge which calls for an interdisciplinary approach that is not always second nature to mega project supervisors.

When VivoCity was opened to much fanfare in 2006, as Singapore's largest mall offering over a million sq ft of retail space, the crowds encountered bottlenecks and navigation problems in the labyrinthine complex. Despite tapping acclaimed Japanese architect Toyo Ito and the latest building technology then, VivoCity's experience showed plans can go awry when attention is not paid to usability details - like signage and human factors that influence traffic flows.

Usability is a concept that is more associated with the information superhighway than in other areas where layouts, movements and interactions warrant a closer study of users. In the digital sphere, designers might leverage design engineering, philosophy, cognitive psychology and ergonomics to improve user experience. The management of transport and public facilities also calls for a look at social behaviour and real- world patterns of usage, among others. Indeed, usability stress tests ought to be the norm before rolling out facilities to the public.

In the case of the MCE, planners had to also consider the needs of fringe commuters. For example, those from Fort Road going to the city via the East Coast Parkway (ECP) need to thread through an East Coast Park service road. Rather than using makeshift directional signs, a broader effort to build public awareness of the changes is needed well before an opening. Maps and videos created for this purpose should also be tested for clarity and effectiveness.

When usability is adequately addressed, users are more likely to rise above inconveniences and appreciate the logic of removing part of the old ECP in the Marina area. The new Central Business District needs room to grow, with new sections blending smoothly with the old. Planning such linkages is as much an art as a science. What will make a difference is always bearing in mind the needs of users.