■ I refer to your editorial of September 19 which tackled ‘traffic on the way to school’.

We will address a number of points raised by your leader in the coming days. For now, may we merely address the part that refers to the size of roundabouts and traffic flows?

There are several factors that determine the size of a roundabout. One of these factors is the traffic capacity that the roundabout is expected to handle. Several other factors that have an impact on roundabout des-igns include deflection at the approach, the lane widths at the approach as well as the lane widths of the circulatory carriageway, the position of the entry lanes, visibility distances for vehicles entering the roundabout and the traffic benefits of a large roundabout versus issues such as land take-up and environmental impact, among others.

All of the above is then regulated by subsidiary legislation 499/57 on New Roads and Road Works Regulations which require roundabouts to be set out according to guidance on the geometric layouts contained in the UK Design Manual for Roads and Bridges (TD16/07):

1.  The minimum value of the inscribed circle diameter for a ‘normal’ or ‘compact’ roundabout is 28m. This is the smallest roundabout that can accommodate the swept path of the ‘design vehicle’;

2.  Design vehicle in Malta is a 12-metre rigid vehicle (route bus, coach and heavy goods vehicle);

3.  Most new roundabouts have been designed with a 28m inscribed circle diameter. However, a larger diameter may be introduced on arterial and distributor roads where space permits, as this increases junc-tion capacity and improves junction performance.

The above therefore reflects technical expertise that rebuts your conclusion that small roundabouts facilitate the flow of traffic. Generally speaking, the larger the diameter of the roundabout the higher the capacity it can handle.