Road reminder: Speed limit road markings and warning signs alert drivers to check their speed.

A Transport Department review has confirmed the maximum speed limit of 50kph for the majority of urban roads should stay.

Overseas experience showed that fatal accidents fell by as much as 44% after lowering the speed limit for urban roads from 60kph to 50.

The recent review made reference to practices in the US, the UK, France, Holland and Canada. It found most countries have adopted a maximum speed limit of 50kph for urban roads, due to the presence of more pedestrians and business activities.

The department's Road Safety & Standards Division Chief Engineer Leung Tak-fai said Australia cut fatal traffic accidents by 44% after it switched to the 50kph limit in 2000.

"A World Health Organisation report also found the survival probability of a pedestrian hit by a car with a speed of 50kph is about 40%, but with a speed of 60kph only 10%," Mr Leung said.

Fatality risk

The WHO World Report on Road Traffic Injury Prevention noted the higher the speed, the shorter the time a driver has to stop and avoid a crash and the more severe the impact is when a collision occurs. A pedestrian's fatality risk is near 60% if the impact speed of a car is 50kph, and 90% if the speed is 60kph.

The report said older pedestrians are more vulnerable. The probability that a pedestrian aged 65 or more will be killed by a car going 75kph is more than 60%, versus 20% for a pedestrian under 15. To read the report summary, click here.

Mr Leung said a review will be conducted regularly, adding the maximum cap will be adjusted for individual road sections when the situation warrants.

In revising the speed limit, considerations are given to road characteristics and designs, the traffic accident rate and survey results on the average speed of vehicles travelling on the specific road section.

"We will also avoid imposing different speed limits on a short road section, as this may cause inconvenience to drivers and impact road safety," Mr Leung added.

151 roads reviewed

Since the 2001 set up of a working group on the speed limit review, 151 road sections have been examined. The speed limit of 25 sections were increased and lowered in 10 sections.

There were 199,449 prosecutions related to speeding from January to November, down 5.8% on the same period in 2005.

Mr Leung reminded drivers the speed limit imposed on a road is the maximum speed that is legally allowed which must not be exceeded at any time. They should also pay heed to the ever-changing traffic situation.