Ireland has been changing speed limits on parts of the road network, including lower limits on many rural local roads.

The reason is simple: a speed limit should reflect the kind of road people are actually using. A narrow local road with bends, houses, farm entrances, walkers and cyclists is not the same environment as a high-quality national route.

Lower limits are part of the Safe System approach. That approach assumes human beings will sometimes make mistakes. The aim is to make sure those mistakes are less likely to result in death or life-changing injury.

Some of the roads we know best can be the roads we take most for granted.

A rural route may feel empty and familiar, but it can change from one bend to the next: a tractor pulling out, a cyclist beyond a crest, mud on the surface, a pedestrian in dark clothing, an animal, a hidden entrance or a car partly across the centre line.

Recent Irish fatality reports have repeatedly shown the importance of higher-speed roads in serious collisions. The lesson is not that rural travel is inherently unsafe. It is that speed, visibility and road geometry can combine quickly.

A road can have the same speed limit in bright sunshine, heavy rain, darkness and fog. But the safe speed is not always the same.

Driving safely means being able to stop within the distance you can see to be clear. If visibility shrinks, your speed should shrink with it. If the surface is wet, grip is reduced and stopping distance grows. If a road is narrow, uneven or unfamiliar, your margin should grow too.

Speeding is not only about the driver who is dramatically over the limit. Risk can rise with the extra few kilometres an hour that begin to feel normal.

The faster you travel, the less time you have to see a problem, understand it and react. Your vehicle also travels farther before you even begin braking, and it needs more distance to stop. If a collision happens, the energy involved is greater.

In our first of twelve bi-weekly programmes about road safety, we speak about the necessity of road safety,

Radio Nova's Brona Cox speaks about Vision Zero - the idea that death or serious injury should never be accepted as an inevitable price of getting from A to B. The national target is to halve road deaths and serious injuries by 2030, on the way towards zero by 2050.

Initial radio promo from presenter Traic Ó Braonáin about the Road Safety programme series to commence on Radio Nova.