Roundabouts only one option for junctions

We refer to the letters from David Lai ("A roundabout solution to traffic woes", October 23), Kevin Lee ("City's drivers puzzled by roundabouts", October 29) and Howard Cowley ("Roundabouts perfect for intersections", November 1).

Currently, roundabouts, signal-controlled junctions and priority (stop/give way) junctions are used on our roads. The choice to adopt types of junctions is based on traffic consideration and land availability. The Transport Department does not have a general objective to replace roundabouts with signal-controlled or priority junctions.

In general, priority junctions are suitable for low to moderate traffic flow.

For higher volume of flow, roundabouts or signal-controlled junctions are considered but they have their pros and cons. While roundabouts cause less delay, long traffic queues may build up if flows from different directions are not balanced. Also, roundabouts occupy more land and cannot have signalised pedestrian crossings. Signal-controlled junctions take up less land and are better able to cater for unbalanced traffic flows and pedestrian crossings. However, delays cannot be avoided, especially during off-peak hours.

As traffic conditions may change over the years, it may be necessary to convert a junction. We consider each case on its merits and choose the most suitable junction type according to the prevailing traffic and site conditions.

It is true that compared with some overseas countries, there are fewer roundabouts in Hong Kong.

There are a number of reasons for this. As Hong Kong is a densely populated city, at many junctions we have to provide signals for pedestrian crossings to cater for the needs of pedestrians and to promote their safety.

Also, traffic patterns as well as land constraints, particularly in built-up areas, may render roundabouts less suitable.

We have considered Mr Cowley's suggestion to convert the signal-controlled junctions along Connaught Road West and Connaught Road Central to roundabouts. The traffic on this stretch of road is predominantly east- or westbound, with less north- or southbound traffic.

With such unbalanced traffic flows, roundabouts are not appropriate. Also, at some junctions there are signalised pedestrian crossings which will have to be relocated or removed if roundabouts are adopted, causing inconvenience to pedestrians.

We hope that the above will help your readers understand better the government's consideration regarding the setting up of roundabouts on our road network.

T.F. Leung, for commissioner for transport