OHJ was as a chief engineer for the Muscat Airport Interchange project for a few months in 2007. He says the original design matches international standards by only 50%, and the safety aspects have been ignored at four key points which have turned accident-prone zones ever since the project has been thrown open for traffic. Proof? Check the crash marks along the safety barriers, he says. He goes on to add that design consultancies which are unable to design highways of international standards must be blacklisted. Here’s a tête-à-tête with OHJ.
What makes you say that Muscat Airport Interchange was badly designed?
In the international standard for highway design, there is a geometrical element used, called transition curve (Known as ‘Clothoide’ in Europe). It enables the car driver to turn his steering wheel from a straight position slowly in the position he needs to drive the car through a curve with a constant radius.
The below image demonstrates the transition curve from a straight point (R=00) by slowly increasing the turn to the point where the transition curve gets permanent.

In the original design, this transition curve was missing and I have repeatedly asked the design consultancy firm to insert transition curves into their design for safety purposes.
They refused to listen to me. The results you can see when you go to the interchange, with crash marks all over the place. I had cautioned the consultancy firm extensively on four critical spots where accidents could occur, and unfortunately, my prediction has come true.
The design firm called me an idiot and they said they will do all what is necessary with the yellow road markings. When I received this idiotic answer from them, I resigned from the contracting company I was working for.
It was very clear the design firm has no clue about transition curve (Clothoide) and for what reason a highway designer inserts this geometrical element into any highway design. This transition curves are not used to please any designer, instead these curves are an essential part of any design.
The mathematical formula for these transition curves is indeed very complex and only a few designers might full understand and be able to handle these curves accurately. I think in Oman, you will find very few engineers who are familiar with the calculation of “Fresnelsche Integrale”, which is the basic mathematical formula for ‘Clothides’.
Why was no consideration given to pedestrians while designing Muscat Airport Interchange in the initial stages?
I was always pressing the design firm and other authorities to find some solution for the pedestrians. Nobody was following my advice and now nearly every day a pedestrian is killed on the spot. It would have been very simple to construct an underpass near the old clock tower during construction of the flyover bridge.
Which are the flyovers/interchanges in Muscat you think have design flaws?
Coming from Wadi Kabir to Al Bustan, the interchange towards Qantab is another sample of very bad design and implementation. There might be a lot more critical spots around Muscat; I just need some more time to identify these locations.
What should be the primary aim of road designers while designing highways?
Stick to international standards – which means safety for road users and pedestrians too.
Do you think road designers have a role to play in reducing accidents in Oman?
By using international standards in Oman’s road and highway projects, you may reduce the rate of accidents by 50% and more. By using a correct design for the Muscat Airport Interchange, the accident rate could have been reduced by 75%. The Airport Interchange is the worst design I have ever seen in my life. And I’ve designed highways for 30 years and up to a value of about 1 billion US dollars.
Are consultants/contractors under pressure to deliver projects which might have an impact on the quality?
There might be some pressure from a client but is should not impact the aspects of road safety. Each accident is a serious matter and any highway designer’s first priority must be safety.